JP2014233851A - Inkjet recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recyclable inkjet recording material having a cockling inhibitory capacity, smoothness/glossy appearance, and tactile properties of levels comparable to those of inkjet recording material using resin-coated support media, above all suitable for glossy photographic print purposes.SOLUTION: The provided inkjet recording material is an inkjet recording material obtained by configuring an ink reception layer atop a support medium where an undercoat consisting of multiple layers is sandwiched in-between the support medium and the ink reception layer, any of undercoat layers (A) constituting the undercoat excluding the layer farthest from the support medium includes hollow particles having a higher hollow ratio and a binder, an undercoat layer (B) adjacent to the undercoat layer (A) on the opposite side of the support medium includes hollow particles having a lower hollow ratio and a smaller average particle diameter and a binder, the surface of the undercoat layer (B) has been smoothed via a calender treatment, the mass ratio of the binder with respect to the hollow particles having a higher hollow ratio within the undercoat layer (A) is higher than the mass ratio of the binder with respect to the hollow particles within the undercoat layer (B), and the hollow particles within the undercoat layer (A) are deformable so as to flatten the undercoat layers (A) by filling peaks and valleys of the support medium via the calender treatment.

Description

  The present invention relates to an ink jet recording material, and particularly to an ink jet recording material excellent in surface smoothness and cockling resistance.

Conventionally, as a support for a photographic inkjet recording material, a resin-coated paper support is generally used from the viewpoint of texture, smoothness and gloss.
The recording material provided with an image forming layer on the resin-coated paper support has good cockling resistance (wave resistance) and glossiness after printing, but the resin-coated paper is coated with polyolefin resin on both sides of the base paper. Since it is a composite material having a layer, there is a disadvantage that it is inferior in recyclability compared with general paper, and the improvement is strongly desired from the viewpoint of preservation of the global environment.

In order to solve the above problem, a photographic ink jet recording material by a casting method using a paper base support has been proposed. (See Patent Documents 1 to 3)
The recording material obtained by the casting method is excellent in smoothness and glossiness, but because of the necessity of using a gas-permeable support, the solvent in the ink penetrates the base paper in a short time after printing, and cockling is likely to occur. The texture is insufficient as a photographic inkjet recording material.

In spite of the casting method, a method of providing an undercoat layer containing a pigment having a small pore volume and a latex adhesive has been proposed for the purpose of suppressing cockling and improving printing bleeding. (See Patent Document 4)
However, the air permeability of the support is indispensable in order to give gloss by the casting method, and the cockling resistance level equivalent to that of a recording body using a resin-coated paper support cannot be achieved.

  There has been proposed an ink jet recording medium in which a barrier layer, an undercoat layer, and a fine pigment ink receiving layer are sequentially provided to simultaneously solve cockling and gloss. (See Patent Document 5) In this recording medium, since the pigment is contained in a high ratio in the barrier layer, the smoothness is significantly inferior to that of the resin-coated paper support, and sufficient gloss cannot be obtained. An ink jet recording medium provided with a latex adhesive barrier layer, a water absorbing layer, and an ink receiving layer has been reported. In this recording medium, although a cockling suppressing function close to that of a resin-coated paper support can be obtained, both the barrier layer and the water-absorbing layer have a low function of filling and smoothing the unevenness of the base paper, so that the resin Smoothness comparable to that of a coated paper support cannot be obtained.

  An ink jet recording medium has been proposed in which an undercoat layer containing an acrylic latex binder is provided under the ink receiving layer. (See Patent Document 7) In this recording medium, both the cockling suppressing function and the smoothness do not reach the resin-coated paper support. In addition, an ink jet recording medium is proposed in which a base paper is provided with a coating layer that has a Cobb water absorption rate mainly composed of pigment and latex, and an ink receiving layer is coated thereon (see Patent Documents 8 and 9). As for the ring suppression function, performance close to that of the resin-coated paper support can be obtained, but the smoothness and glossiness are inferior to those of the resin-coated paper support.

On the other hand, an ink jet recording medium has been proposed in which a coating layer containing an organic pigment is provided under the ink receiving layer. (See Patent Document 10) In this recording medium, the coating layer containing an organic pigment assists ink absorbability and has a very low cockling suppressing function.
The smoothness and glossiness are also inferior to the resin-coated paper support.

  In addition, a method for manufacturing an ink jet recording medium in which an undercoat layer is provided on a paper support by a casting method to form an ink receiving layer has been proposed. (Patent Document 11) In this method, high smoothness is obtained at the time when the undercoat layer is formed. However, since the water permeability of the undercoat layer is large, the water in the coating solution is absorbed by the support when the ink receiving layer is applied. Since the unevenness of the support becomes large, the resin coated paper support cannot have the same smoothness. Also, the cockling suppression function is very low.

  As described above, an ink jet recording medium having smoothness, glossiness and cockling resistance equivalent to that of a resin coated support is not realized without using a resin coated paper support.

  An object of the present invention is to provide a recyclable ink jet which has a cockling suppression ability, smoothness / glossiness and texture equivalent to those of an ink jet recording material using a resin-coated paper support, and is particularly suitable for glossy photographic printing. It is to provide a recording material.

The above-described problems are solved by the following inkjet recording materials (1) to (7) of the present invention.
(1) “Inkjet recording material having an ink receiving layer provided on a support has an undercoat composed of a plurality of layers between the support and the ink receiving layer. Any undercoat layer (A) excluding a layer far from the support contains hollow particles having a higher hollowness and a binder, and is adjacent to the opposite side of the undercoat layer (A) from the support The undercoat layer (B) contains hollow particles having a lower hollow ratio and a smaller average particle size and a binder, and the surface of the undercoat layer (B) is smoothed by calendaring. In the undercoat layer (A), the mass ratio of the binder with respect to the amount of hollow particles having a higher hollowness ratio is such that the amount of hollow particles in the undercoat layer (B) is The hollow particles in the undercoat layer (A) are flattened by filling the unevenness of the support by the calendering process. An ink jet recording material characterized by being easily deformed. "
(2) “The hollow particles in the undercoat layer (A) have a hollowness of 70% or more and 95% or less, and the mass of the binder contained in the undercoat layer (A) is the undercoat layer. 150% or more and 550% or less of the mass of the hollow particles contained in (A) and contained in the undercoat layer (B) adjacent to the opposite side of the support of the undercoat layer (A). The hollow particles have an average particle size of 0.3 μm or more and 1 μm or less, and the mass of the binder contained in the undercoat layer (B) is the average particle size contained in the undercoat layer (B). The inkjet recording material according to (1), wherein the mass of the hollow particles of 0.3 μm or more and 1 μm or less is 60% or more and 200% or less. ”
(3) “The inkjet recording material according to (1) or (2), wherein the hollow particles contained in the undercoat layer (A) have an average particle diameter of 1 μm to 10 μm”;
(4) “The hollow ratio of hollow particles having an average particle size of 0.3 μm or more and 1 μm or less contained in the undercoat layer (B) is 30% or more and 80% or less,” described in (2) or (3) Inkjet recording material. "
(5) The first (1), wherein the undercoat layer (B) contains a crosslinking agent that gels the binder of the ink receiving layer, and the ink receiving layer is adjacent to the undercoat layer (B). The inkjet recording material according to any one of (4) to (4). "
(6) The inkjet recording according to any one of (1) to (5), wherein the undercoat layer (A) contains an inorganic pigment having an average particle size of 0.1 μm or more and an average particle size of 1 μm or less. material.",
(7) “The surface of the undercoat layer (B) is smoothed by calendering by calendering a mirror roll having a surface temperature of 45 ° -80 ° in contact with the surface of the undercoat layer (B). The inkjet recording material according to any one of (1) to (6).

  As will be understood from the following detailed and specific description, according to the present invention, the ink jet recording material using the resin-coated paper support has the same level of cockling resistance, smoothness / glossiness and texture as those of the inkjet recording material. Thus, a recyclable ink jet recording material can be obtained.

<Base paper>
There is no restriction | limiting in particular as a base paper, According to the objective, it can select suitably. Generally, it is comprised as a main component the wood pulp and the filler contained as needed. As the wood pulp, various chemical pulps, mechanical pulps, regenerated pulps and the like can be used, and these pulps can be beaten by a beating machine in order to adjust paper strength, papermaking suitability, and the like. The beating degree (freeness) of the pulp is not particularly limited, but is generally about 250 to 550 ml (CSF: JIS P8121). It is preferable to adjust to about 300-500 ml.

  Fillers are blended for the purpose of imparting opacity and the like, and include calcium carbonate, clay, kaolin, white clay, talc, titanium oxide, diatomaceous earth, barium sulfate, aluminum hydroxide, magnesium hydroxide and the like. In particular, calcium carbonate is preferable because it becomes a substrate with high whiteness and glossiness of the ink jet recording material is enhanced. The content (ash content) of the filler in the paper base material is preferably about 1 to 30%, but if it is too much, the paper strength tends to be weakened, so the preferable content of the filler is 5 to 20%.

  In addition to sizing agents, paper strength enhancers, fixing agents, cationizing agents, yield improvers, dyes, fluorescent brighteners, pH adjusters, antifoaming agents, etc. may be added to the base paper as auxiliaries. it can. Furthermore, in the size press process of the paper machine, starch, polyvinyl alcohol, cationic resin, etc. can be applied and impregnated to adjust the surface strength, Cobb water absorption, and the like.

  Examples of the sizing agent include fatty acid salts, rosin derivatives such as rosin and maleated rosin, paraffin wax, alkyl ketene dimer, alkenyl succinic anhydride (ASA), compounds containing higher fatty acids such as epoxidized fatty acid amide, and the like. Can be mentioned. Examples of the dry paper strength enhancer include cationized starch, cationized polyacrylamide, anionized polyacrylamide, amphoteric polyacrylamide, and carboxy-modified polyvinyl alcohol. Examples of the wet paper strength enhancer include polyamine polyamide epichlorohydrin, melamine resin, urea resin, and epoxidized polyamide resin. Examples of the fixing agent include polyvalent metal salts such as aluminum sulfate and aluminum chloride, and cationic polymers such as cationized starch.

Density of the base paper is in the range of 0.6 to 1.2 g / cm ^3, preferably 0.7~1.0g / cm ³ in order to give texture of resin coated paper, 0.80 to 0. 95 g / cm ³ is more preferable. The thickness of the base paper is not particularly limited, and is usually 50 to 500 μm. 100 to 300 μm is preferable and 150 to 250 μm is more preferable in view of paper stiffness and rigidity. There is no restriction | limiting in particular in the basic weight of the said base paper, 50-300 g / m < ² > is preferable, and 100-250 g / m < ² > is more preferable from balance with rigidity and a feeling of weight.

<Undercoat>
The ink jet recording material of the present invention has at least two undercoat layers on the surface of the base paper on which the image forming layer is provided in order to obtain cockling resistance, surface glossiness, and smoothness similar to those of a resin-coated paper support. Have Of the layers constituting the undercoat layer, any undercoat layer (A) excluding the layer farthest from the support contains hollow particles having a hollow ratio of 70% to 95% and a binder, The undercoat layer (B) adjacent to the side opposite to the support of the undercoat layer (A) contains hollow particles having an average particle size of 0.3 μm or more and 1 μm or less and a binder. Furthermore, the surface of the undercoat layer (B) is smoothed by a calendar process. The hollow ratio of the hollow particles in the present invention is a value obtained by dividing the volume of the hollow part of the hollow particles by the volume of the outer shape of the hollow particles. The average particle diameter of the hollow particles is a volume-based average particle diameter obtained by measuring a dilute dispersion of hollow particles with a laser diffraction / scattering particle size distribution analyzer.

-Hollow particles-
Hollow particles having a hollow ratio of 70% or more and 95% or less contained in the undercoat layer (A) are, for example, organic hollow particles, and depending on the type and properties of the support and the binder, resin hollow particles are preferable. Thermoplastic resin hollow particles are preferred. The thermoplastic resin hollow particles are hollow particles having a thermoplastic resin as a shell. Examples of the thermoplastic resin include polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, poly (meth) acrylic acid ester, Examples thereof include polyacrylonitrile, polybutadiene, and copolymer resins thereof. Among these, copolymer resins mainly composed of vinylidene chloride or acrylonitrile such as acrylonitrile-vinylidene chloride-methyl methacrylate copolymer and acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer are particularly preferable.

  When the undercoat layer (A) contains hollow particles having a hollow ratio of 70% to 95%, the density of the undercoat layer (A) is reduced. As a result, the thickness of the undercoat layer (A) is increased as compared with the case of containing hollow particles having a hollow ratio of less than 70% or the case of containing no hollow particles, and the cockling suppressing effect at the time of ink jet printing is improved. . In addition, during calendering of the surface of the undercoat layer (B), the undercoat layer (A) is easily deformed so as to fill the unevenness of the base paper and flatten it, so that the surface of the undercoat layer (B) is greatly smoothed. The effect to improve is acquired. On the other hand, when the hollow ratio of the hollow particles contained in the undercoat layer (A) exceeds 95%, the undercoat layer (A) may be excessively crushed and the surface of the undercoat layer (B) may not be sufficiently smoothed.

The average particle diameter of the hollow particles contained in the undercoat layer (A) is preferably 1 μm or more and 10 μm or less. When the average particle diameter exceeds 10 μm, the smoothness of the surface of the undercoat layer (B) may not be sufficiently obtained. Further, hollow particles having an average particle diameter of less than 1 μm may not be practical because it is difficult to produce hollow particles having a high hollow ratio.
It is known that the acquisition of hollow particles of various sizes and various hollownesses made of such thermosetting resins and thermoplastic resins can be adjusted and manufactured by various methods, and many commercially available products are available. . Specific examples of the method for producing hollow particles include suspension polymerization in the presence of a water-insoluble non-polymerizable organic solvent as disclosed in JP-B-36-9168 and JP-A-37-14327. A method of obtaining polymer particles containing the solvent in the inner pores by carrying out emulsion polymerization and removing inclusions from the polymer particles, a hydrophilic monomer disclosed in Japanese Patent Publication No. 5-40770 Then, by carrying out suspension polymerization or emulsion polymerization of a dispersion in which a crosslinkable monomer and an oily substance coexist, polymer particles containing the oily substance in the inner pores are obtained, and then the oily substance is removed to obtain a hollow polymer. Method for obtaining particles, as disclosed in JP-A-9-19635, heating microcapsules enclosing volatile substances such as butane and pentane, and gasifying the volatile substances A method of obtaining hollow particles by stretching, a basic substance acting on polymer particles comprising an alkali-swellable core part and a shell part covering the same, as disclosed in JP-A-56-32513 The core part is made of a vinyl acetate polymer, as disclosed in JP-A-2-173101. / The method of hydrolyzing the core part of the shell-type polymer is exemplified, but it is not limited to these production methods.
Specific examples of commercially available hollow particles include the “Ropeque” series released by Rohm and Haas Japan, the “SX” series from JSR, and the “MH” series from Nippon Zeon. The Matsumoto Microsphere's “Matsumoto Microsphere” series, Sekisui Chemical's “Advancel” series, Nippon Philite's “Expansel” series, etc.

  The mass of the binder contained in the undercoat layer (A) is preferably from 150% to 550% of the mass of the hollow particles having a hollow ratio of from 70% to 95% contained in the undercoat layer (A). When the mass of the binder is less than 150% of the mass of the hollow particles having a hollow ratio of 70% or more and 95% or less, voids are generated between the particles of the hollow particles without being filled with the binder, and a cockling suppressing effect is sufficiently obtained. There may not be. Moreover, when the mass of the binder exceeds 550% of the mass of the hollow particles having a hollow ratio of 70% or more and 95% or less, the undercoat layer (A) is hardly deformed during the calender treatment of the surface of the undercoat layer (B). Thus, the surface of the undercoat layer (B) may not be sufficiently smoothed.

Hollow particles having an average particle diameter of 0.3 μm or more and 1 μm or less contained in the undercoat layer (B) are organic hollow particles, and thermoplastic resin hollow particles are preferable. The thermoplastic resin hollow particles are hollow particles having a thermoplastic resin as a shell, and examples of the thermoplastic resin include polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, poly (meth) acrylate, Examples include acrylonitrile, polybutadiene, and copolymer resins thereof.
Among these, polystyrene, poly (meth) acrylic acid ester, and copolymerization thereof are particularly preferable because they can easily produce hollow particles of 1 μm or less.

  When the undercoat layer (B) contains hollow particles having an average particle size of 0.3 μm or more and 1 μm or less, smoothness equivalent to that of a resin-coated paper support can be obtained. When the average particle diameter of the hollow particles contained in the undercoat layer (B) exceeds 1 μm, unevenness due to the hollow particles remains even after the calendar treatment, and the surface smoothness of the undercoat layer (B) is lowered. On the other hand, hollow particles having an average particle diameter of less than 0.3 μm are difficult to produce, or even if they can be produced, the hollow ratio is very small. It is not practical to contain.

  The hollow ratio of the hollow particles having an average particle diameter of 0.3 μm or more and 1 μm or less contained in the undercoat layer (B) is preferably 30% or more and 80% or less. When the hollow ratio of hollow particles having an average particle size of 0.3 μm or more and 1 μm or less exceeds 80%, the surface of the undercoat layer (B) is likely to be damaged, and excessive care may be required in handling the inkjet recording material. is there. When the hollow ratio of the hollow particles having an average particle size of 0.3 μm or more and 1 μm or less is less than 30%, the smoothness of the surface of the undercoat layer (B) after the calendar treatment may not be sufficiently obtained.

  The mass of the binder contained in the undercoat layer (B) is preferably 60% or more and 200% or less of the mass of the hollow particles having an average particle diameter of 0.3 μm or more and 1 μm or less contained in the undercoat layer (B). When the mass of the binder is less than 60% of the mass of hollow particles having an average particle size of 0.3 μm or more and 1 μm or less, voids are generated between the hollow particles without being filled with the binder, and the surface of the undercoat layer (B) The smoothness of the film may be reduced. Moreover, when the mass of the binder exceeds 200% of the mass of the hollow particles having an average particle diameter of 0.3 μm or more and 1 μm or less, the undercoat layer (B) is deformed during the calender treatment of the surface of the undercoat layer (B). It becomes difficult and the surface of the undercoat layer (B) may not be sufficiently smoothed.

-Binder-
Synthetic resin latex is preferably used as the main component of the binder contained in each layer constituting the undercoat. Specific examples of the synthetic resin latex include styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylonitrile-butadiene copolymer, acrylic copolymer, styrene-acrylic copolymer, and styrene copolymer. , Vinyl acetate copolymer, ethylene-vinyl acetate copolymer, vinyl acetate-ethylene-vinyl chloride olefin copolymer, (poly) urethane copolymer, ionomer, and ionomer copolymer.

As the binder to be contained in the undercoat layer (A), a synthetic resin latex having a high water barrier property and a softening temperature of 60 ° C. or less is preferably used. By using a binder having a high water barrier property, an effect of suppressing cockling can be obtained. Further, when an ink receiving layer is provided on the undercoat layer, deterioration of smoothness due to water absorption of the base paper can be prevented.
In addition, when the softening temperature is 60 ° C. or less, high smoothness can be obtained by calendering the surface of the undercoat layer (B). As the synthetic resin latex having such characteristics, acrylic copolymers, ionomers and ionomer copolymers are particularly preferable.

As the binder to be contained in the undercoat layer (B), a binder that is easy to be smoothed by a calendar process and hardly sticks to a glossy roll of a calendar is preferable.
Examples of such synthetic resin latex include polyvinyl acetate and polyvinyl acetate copolymer, and ethylene-vinyl acetate copolymer is particularly preferable.

  If necessary, the undercoat layer (A) or the undercoat layer (B) may contain a binder other than the synthetic resin latex. Specific examples of binders other than synthetic resin latex include starches such as oxidized starch, etherified starch and esterified starch, polyvinyl alcohol and modified products thereof, casein, gelatin, cellulose ethers, water-soluble acrylic resins and the like. Sexual binders. When these water-soluble banders are used, it is preferable to use a cross-linking agent of these water-soluble binders together for the purpose of preventing the cockling suppressing effect and the deterioration of the surface smoothness.

-Other ingredients-
The undercoat layer (A) or the undercoat layer (B) can contain an inorganic pigment in order to improve opacity and whiteness. The average particle diameter of the inorganic pigment is preferably 0.1 μm or more and 1 μm or less. The average particle size of the inorganic pigment is a volume-based average particle size obtained by measuring a dilute dispersion of an inorganic pigment with a laser diffraction / scattering particle size distribution analyzer. If the average particle system of the inorganic pigment is less than 0.1 μm, the effect of improving opacity and whiteness may be insufficient. On the other hand, if the average particle size of the inorganic pigment exceeds 1 μm, the smoothness of the ink jet recording material of the present invention may be insufficient. The inorganic pigment is particularly preferably contained in the undercoat layer (A). By including an inorganic pigment in the undercoat layer (A), it is possible to achieve improvement in opacity and whiteness without impairing the smoothness of the inkjet recording material.

  The undercoat layer (A) or the undercoat layer (B) can contain a fluorescent dye in order to improve whiteness. The kind of fluorescent dye is not particularly limited. By including the fluorescent dye in the undercoat layer (B), the whiteness can be improved efficiently.

  A color pigment can be added to the undercoat layer (A) or the undercoat layer (B) in order to adjust the hue of the ink jet recording material. By including the color pigment in the undercoat layer (B), the hue can be adjusted more easily.

-Application amount-
The coating amount of the undercoat layer (A) is preferably from ^{3~25g / m 2, 5~15g / m} 2 is particularly preferred. If the coating amount is less than 3 g / m ² , the smoothness and cockling suppression effect of the ink jet recording material may be insufficient. Moreover, when the coating amount exceeds 25 g / m ² , the effect is saturated.
The coating amount of the undercoat layer (B) is preferably from ^{3~30g / m 2, 5~20g / m} 2 is particularly preferred. If the coating amount is less than 3 g / m ² , the smoothness of the ink jet recording material may be insufficient. Further, when the coating amount exceeds 30 g / m ² , the effect is saturated.

  In the ink jet recording material of the present invention, another coating layer may be provided between the base paper and the undercoat layer (A) and between the undercoat layer (B) and the ink receiving layer. The pigment or binder used in the other coating layer is not particularly limited, but the surface smoothness is not impaired when another coating layer is provided between the undercoat layer (B) and the ink receiving layer. It is preferable to provide a coating layer.

  The undercoat according to the present invention can also be provided on the surface opposite to the surface on which the ink receiving layer is provided for the purpose of adjusting the curl of the ink jet recording material.

-Application method-
The coating method of the undercoat layer including the undercoat layer (A) and the undercoat layer (B) is not particularly limited. Specific examples of coating methods include general coating devices, such as blade coaters, roll coaters, air knife coaters, rod coaters, gate roll coaters, curtain coaters, gravure coaters, flexographic gravure coaters, spray coaters, size presses, etc. Various devices. A blade coater, a rod coater, and a wire bar coater are particularly preferable because a smooth coated surface can be easily obtained.

<Calendar processing>
The surface of the undercoat layer (B) is smoothed by calendering after forming the undercoat layer (B). The calendar treatment is most preferably performed such that the surface of the undercoat layer (B) is in contact with the calendar metal roll. The calendar pressure (linear pressure) is preferably 50 to 400 Kg / cm, more preferably 70 to 250 Kg / cm, and particularly preferably 100 to 200 Kg / cm. When the calendar pressure is too low or too high, it is difficult to obtain smoothness, and it is preferable that the calender pressure is processed under conditions that provide high smoothness.

  The surface temperature of the metal roll of the calendar is preferably 20 ° C to 120 ° C, more preferably 40 ° C to 100 ° C, and particularly preferably 45 ° C to 80 ° C. The calendar processing speed is preferably in the range of 30 to 1200 m / min, more preferably 50 to 700 m / min. If the calendar speed is too slow, it tends to stick to the calendar roll and the coating layer may peel off. On the other hand, if it is too fast, the effect of smoothing is reduced.

  In order to obtain higher smoothness, the surface temperature of the undercoat layer (B) immediately before the calendar is preferably in the range of 20 to 90 ° C, more preferably 25 to 80 ° C, and particularly preferably 30 to 70 ° C. If the paper surface temperature is too low, the smoothing effect may not be sufficiently obtained. If the paper surface temperature is too high, a problem of sticking to the calendar roll may occur.

<Ink receiving layer>
Next, the ink receiving layer according to the present invention will be described. As the ink receiving layer, a matte tone, glossy or super glossy ink receiving layer can be used without particular limitation. The material constituting the ink receiving layer includes various inorganic fine particles and a binder as main components, but is not particularly limited. Among such ink receiving layers, an ink receiving layer containing inorganic fine particles having an average particle size of 0.1 μm to 0.3 μm is particularly preferable. Here, the average particle diameter indicates the average particle diameter of the secondary particles of the inorganic fine particles, and is an average value of the projected area circle equivalent diameter of the dispersed secondary particles (aggregated particles) observed using an electron microscope. . Here, the projected area equivalent circle diameter is the diameter of a circle having an area equal to the projected area of the particles. The average particle size is obtained by observing the inorganic fine particles with an electron microscope at a magnification at which the secondary particle size can be discriminated, and obtaining the projected area equivalent diameter of each of the 100 inorganic fine particles existing in an arbitrary fixed area. It is a value obtained by averaging the number of equivalent diameters. By providing the release layer according to the present invention on an ink receiving layer containing inorganic fine particles having an average particle size of 0.1 μm or more and 0.3 μm or less, ink-jet recording with good color development and ink absorbability and high surface gloss Material can be obtained.

  The content of inorganic fine particles having an average particle size of 0.1 μm or more and 0.3 μm or less contained in the ink receiving layer is preferably 50% by mass or more based on the mass of the entire ink receiving layer. If the content is less than 50% by mass, ink jet recording suitability may be lowered or surface gloss may be lowered.

  Examples of the inorganic fine particles having an average particle diameter of 0.1 μm or more and 0.3 μm or less according to the present invention include known colorless or white metal oxides such as amorphous synthetic silica, alumina, alumina hydrate, and titanium oxide. Examples thereof include fine particles, calcium carbonate, and magnesium carbonate, and extender pigments made of white or colorless inorganic fine particles are preferable. From the viewpoint of ink absorbability, amorphous synthetic silica, alumina or alumina hydrate is particularly preferable.

  The amorphous synthetic silica can be roughly classified into gas phase method silica, wet method silica, and others depending on the production method, and gas phase method silica can be preferably used from the viewpoint of ink absorbability.

  The gas phase method 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 silica is commercially available from Nippon Aerosil Co., Ltd. as Aerosil, and from Tokuyama Co., Ltd. as Reolosil.

  Vapor phase silica produced by a normal method has an average aggregate particle size of 1 μm or more, and is used after being finely pulverized.

  As a pulverization method, a wet dispersion method in which silica dispersed in an aqueous medium is mechanically pulverized can be preferably used. As a specific method for finely pulverizing the vapor phase silica, the silica particles and the cationic compound are mixed in water (which may be added first or at the same time), or each dispersion or aqueous solution. And a preliminary dispersion is obtained using at least one of a dispersing device such as a serrated blade type disperser, a propeller blade type disperser, or a rotor stator type disperser. If necessary, an appropriate low boiling point solvent may be added.

  Next, by applying a stronger mechanical means to the preliminary dispersion of vapor phase silica, a vapor phase silica dispersion having an average particle size of 0.1 μm or more and 0.3 μm or less is obtained. As a mechanical means, a known method can be adopted, for example, a media mill such as a ball mill, a bead mill, a sand grinder, a high pressure homogenizer, a pressure disperser such as an ultra high pressure homogenizer, an ultrasonic disperser, a thin film swirl disperser, etc. Can be used.

The wet method silica is further classified into precipitation method silica, gel method silica, and sol method silica according to the production method.
Precipitated silica is produced by reacting sodium silicate and sulfuric acid under alkaline conditions, and the silica particles that have grown are agglomerated and settled, and are then commercialized through the steps of filtration, washing, drying, pulverization and classification. Precipitated silica is commercially available, for example, from Tosoh Silica Co., Ltd. as a nip seal and from Tokuyama Co., Ltd. as a Toxeal.

  Gel silica is produced by reacting sodium silicate and sulfuric acid under acidic conditions. During aging, the microparticles dissolve and reprecipitate so as to bind the other primary particles, so that the distinct primary particles disappear and form relatively hard aggregated particles having an internal void structure. For example, it is commercially available as nip gel from Tosoh Silica Co., Ltd., and as syloid and silo jet from Grace Japan Co., Ltd.

  The sol method silica is also called colloidal silica, and is obtained by heating and aging a silica sol obtained through metathesis of sodium silicate acid or through an ion exchange resin layer. For example, it is commercially available as Snowtex from Nissan Chemical Industries, Ltd. Yes.

  Precipitated silica and gel silica prepared by ordinary methods have an average agglomerated particle size of 1 μm or more, and are used after being finely pulverized.

As a pulverization method, a wet dispersion method in which silica dispersed in an aqueous medium is mechanically pulverized can be preferably used. At this time, an increase in the initial viscosity of the dispersion is suppressed, high-concentration dispersion is possible, and pulverization / dispersion efficiency is increased, so that the oil can be pulverized into fine particles. It is preferable to use precipitated silica of 5 μm or more. By using a high-concentration dispersion, the productivity of recording paper is also improved.
The oil absorption is measured based on the description of JIS K-5101.

  Specific methods for finely pulverizing precipitated silica and gel silica include mixing silica particles and a cationic compound in water (which may be added first or at the same time), or dispersing each of them. A liquid or an aqueous solution is mixed, and a preliminary dispersion is obtained using at least one of a dispersing device such as a serrated blade type disperser, a propeller blade type disperser, or a rotor stator type disperser. If necessary, an appropriate low boiling point solvent may be added.

  The pre-dispersion of precipitated silica and gel silica is preferably higher in solid content, but cannot be dispersed when the concentration is too high. Therefore, the preferred range is 15 to 40% by mass, more preferably 20 to 35%. % By mass.

  Next, by applying a stronger mechanical means, a wet process silica dispersion having an average particle size of 0.1 μm or more and 0.3 μm or less is obtained. As a mechanical means, a known method can be adopted, for example, a media mill such as a ball mill, a bead mill, a sand grinder, a high pressure homogenizer, a pressure disperser such as an ultra high pressure homogenizer, an ultrasonic disperser, a thin film swirl disperser, etc. Can be used.

  As the alumina, γ-alumina, which is a γ-type crystal of aluminum oxide, is preferable, and among them, a δ group crystal is preferably used. γ-alumina can make primary particles as small as about 10 nm. Usually, secondary particle crystals of several thousand to several tens of thousands nm are pulverized with ultrasonic waves, a high-pressure homogenizer, a counter-impact type jet pulverizer, or the like. Can be used.

The alumina hydrate is represented by a constitutive formula of Al ₂ O ₃ .nH ₂ O (n = 1 to 3).
The case where n is 1 represents an alumina hydrate having a boehmite structure, and the case where n is greater than 1 and less than 3 represents an alumina hydrate having a pseudoboehmite structure. The alumina hydrate can be obtained by a known production method such as hydrolysis of an aluminum alkoxide such as aluminum isopropoxide, neutralization of an aluminum salt with an alkali, hydrolysis of an aluminate.

  The average primary particle diameter of the inorganic fine particles according to the present invention is preferably 30 nm or less, and in order to obtain higher gloss, it is preferably 15 nm or less, more preferably 3 to 15 nm, and particularly preferably 3 to 10 nm. .

Further, the specific surface area of the inorganic fine particles by the BET method is preferably 200 m ² / g or more, and more preferably 250 to 500 m ² / g.

  The average primary particle diameter as used in the present invention refers to the average particle diameter obtained by observing fine particles with an electron microscope and taking the diameter of a circle equal to the projected area of each of 100 primary particles present within a certain area as the particle diameter of the particles. The BET method referred to in the present invention is one of the powder surface area measurement methods by the vapor phase adsorption method, and is a method for determining the total surface area of a 1 g sample from the adsorption isotherm, that is, the specific surface area. is there. Usually, nitrogen gas is often used as the adsorbed gas, and the most frequently used method is to measure the amount of adsorption from the change in pressure or volume of the gas to be adsorbed. The most prominent expression for expressing the isotherm of multimolecular adsorption is the Brunauer, Emmett, and Teller equation, called the BET equation, which is widely used for determining the surface area. The adsorption amount is obtained based on the BET equation, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.

A conventionally well-known thing is mentioned as a binder contained in an ink receiving layer.
It is preferable that the main component is polyvinyl alcohol selected from polyvinyl alcohol and modified polyvinyl alcohol in terms of adhesion to the pigment and easy formation of a non-film-formed release layer. Polyvinyl alcohols having a polymerization degree of 1700 or more are preferable, and polyvinyl alcohols having a polymerization degree of 2500 or more are more preferable from the viewpoint of controlling ink absorbability and the smoothness of the ink receiving layer surface. Two or more binders may be used in combination for the purpose of improving the coating layer strength, ink absorbability, and the like.
The content of the binder contained in the ink receiving layer is preferably less than 50% by mass with respect to the mass of the entire ink receiving layer. If the content is 50% by mass or more, ink jet recording suitability may be deteriorated.

  In addition to the inorganic fine particles and binder, the ink-receiving layer may contain various auxiliary agents such as dispersants, thickeners, antifoaming agents, colorants, antistatic agents, and antiseptics that are used in general coated paper production. Added. A cationic compound may be added and used for ink fixing.

Examples of the cationic compound include 1) polyalkylene polyamines such as polyethylene amine and polypropylene polyamine, or derivatives thereof, 2) acrylic resins having secondary amine groups, tertiary amine groups, and quaternary ammonium groups, 3 ) Polyvinylamine, polyvinylamidine, 5-membered ring amidines, 4) Dicyan cation resin represented by dicyandiamide-formalin polycondensate, 5) Polyamine cation resin represented by dicyandiamide-diethylenetriamine polycondensate, 6) Epo chlorohydrin - dimethylamine addition polymers, 7) dimethyldiallylammonium chloride -SO ₂ copolymer, 8) diallylamine -SO ₂ copolymer, 9) dimethyldiallylammonium chloride polymer, 10) polymer of allylamine salt, 11 Examples of commercially available products include dialkylaminoethyl (meth) acrylate quaternary salt polymers, 12) acrylamide-diallylamine salt copolymers, 13) aluminum salts such as polyaluminum chloride, polyaluminum acetate, and polyaluminum lactate. . In addition, as addition amount of a cationic compound, 1-30 mass parts is preferable with respect to 100 mass parts of pigments, and 2-15 mass parts is more preferable.

  The ink receiving layer preferably contains a cross-linking agent that cross-links the binder as necessary. In particular, an embodiment in which the inorganic fine particle and the binder are used in combination and the porous layer is further cured by a crosslinking reaction between the crosslinking agent and the binder is preferable. Specific examples of the crosslinking agent include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, bis (2-chloroethyl) urea, 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 US Pat. No. 2,732,316, isocyanates as described in US Pat. No. 3,103,437, US Pat. No. 3,017,280, Aziridine compounds as described in US Pat. No. 2,983,611, US Pat. No. 3,100,704 Carbodiimide compounds such as those described in detail, epoxy compounds as described in US Pat. No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, ethylenediamine, diethylenetriamine, triethylenediamine, meta Polyamine compounds such as xylylenediamine, norbornanediamine, 1,3-bisaminomethylcyclohexane, carbohydrazide, succinic dihydrazide, adipic dihydrazide, citric acid trihydrazide, polyhydrazide compounds such as sebacic acid dihydrazide, 4,4 ′ -Reaction products of polyisocyanate and hydrazine such as ethylene disemicarbazide and 4,4'-hexamethylene disemicarbazide, polymers such as polyacrylic acid hydrazide Hydrazide, organic titanium compounds such as titanium lactate compound and titanium glycolate compounds, boric acid, there is an inorganic crosslinking agent such as borate, it can be used in combination thereof one or more.

The ink receiving layer may be composed of a single layer or a plurality of layers. The coating amount of the ink receiving layer is not particularly limited, but is 3 to 30 g / m ² , preferably 5 to 25 g / m ² , particularly preferably 10 to 25 g / m ^{2 in} terms of the coating amount of the entire ink receiving layer. It is. If the coating amount of the entire ink receiving layer is less than 3 g / m ² , the ink receiving property may be insufficient, and if it exceeds 30 g / m ² , the ink receiving property may be excessive, resulting in poor economic efficiency. .

  The ink receiving layer can be applied by wire bar coater, kiss roll coater, lip coater, direct roll coater, offset roll coater, gravure roll coater, reverse roll coater, rod coater, blade coater, air knife coater, slit die coater. It is performed by various coating devices such as a curtain coater. Drying after coating can be performed by a method of blowing hot air, a method of irradiating infrared rays, a method of blowing dehumidified air, or the like. In the case of forming an ink receiving layer containing fine inorganic fine particles having an average particle size of 0.5 μm or less, the ink receiving layer is dried before the ink receiving layer is dried for the purpose of preventing cracking of the ink receiving layer in the drying step. It is preferable to gel the binder of the receiving layer. As a specific method for gelling the binder of the ink receiving layer, a method of adding a binder crosslinking agent to the ink receiving layer, applying the gel before the coating liquid gels, and gelling on the support, ink Add a temperature-responsive cross-linking agent to the receptor layer, and after application, gel by heating or cooling; add a binder that gels by irradiation with active energy rays such as ultraviolet rays or electron beams to the ink receptor layer In addition, after the ink receiving layer is applied, a gel is formed by irradiation with active energy rays, and a binder crosslinking agent for the ink receiving layer is provided on the surface of the support on which the ink receiving layer is applied. Examples thereof include a method of applying a layer, and a method of applying a cross-linking agent to an undried ink receiving layer after applying the ink receiving layer to a support.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. Further, “parts” and “%” shown in the examples indicate parts by mass and mass% unless otherwise specified.

A method for evaluating the ink jet recording material will be described.
<Surface roughness>
Using a laser microscope (manufactured by Keyence Co., Ltd., trade name: VK-8500), line roughness at a measuring distance of 5.5 mm was measured in a color ultra-deep mode with an objective lens of 2.5 times and a 0.5 μm step. The obtained data was subjected to + -2 simple smoothing, no dark cut, and no bright cut, and the ten-point average roughness was determined to evaluate the surface roughness.

<Glossiness>
The glossiness of 20 ° and 60 ° of the ink receiving layer surface of the ink jet recording material was measured using a gloss meter (trade name: VG 200, manufactured by Nippon Denshoku Industries Co., Ltd.) to evaluate the gloss.

<Cockling resistance>
Using an inkjet printer (Seiko Epson Corporation, trade name: EP-302) and dye ink (Seiko Epson Corporation, trade name: IC6CL50), a red solid image is printed on the entire surface of the A4 size inkjet recording material. The cockling after 5 minutes from the printing was observed and evaluated by the following five-stage numerical values.
The larger the value, the better the characteristics.
5: State where no cockling occurs.
4: A state where slight cockling with a height of 1 mm or less occurs.
3: A state in which cockling exceeding 1 mm in height and 2 mm or less occurs.
2: A state in which cockling exceeding 2 mm in height and 5 mm or less occurs.
1: A state in which cockling exceeding 5 mm in height occurs.

<Image density>
Paper type: EPSON photographic paper, printing type: standard, color correction using ink jet printer (Seiko Epson Corporation, trade name: EP-302), dye ink (Seiko Epson Corporation, trade name: IC6CL50) Black solids were printed under automatic conditions, and the density after 24 hours from the printing was measured with a densitometer (trade name: RD-918, manufactured by Macbeth) to evaluate the image density.

Next, preparation of an undercoat coating solution will be described.
<< Undercoat layer (A) coating liquid >>
<Undercoat layer (A) coating solution 1>
The following composition was mixed and the undercoat layer (A) coating liquid 1 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle diameter 4.1 μm, hollow ratio 85%) ... 18.8 parts acrylic resin emulsion (Mitsui Chemicals) (Product name: Bonron S-1120, solid content: 43%) Agent (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.08 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 30.6 parts

<Undercoat layer (A) coating solution 2>
The following composition was mixed and the undercoat layer (A) coating liquid 2 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle diameter 4.0 μm, hollow ratio 70%) ... 18.8 parts acrylic resin emulsion (Mitsui Chemicals) (Product name: Bonron S-1120, solid content: 43%) Agent (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.08 part Water ・ ・ ・ ・ ・ ・... 30.6 parts

<Production>
To 1000 ml of 1% aqueous sodium hydroxide solution, 5.0 g of the inkjet recording material cut into 1 cm × 1 cm was added, and the mixture was placed in a home mixer and stirred for 5 minutes. The undissolved material of the obtained slurry was visually evaluated according to the following criteria.
(Double-circle): The magnitude | size of all the disaggregation pieces is 1 mm x 1 mm or less.
○: There are a few pieces of disaggregation pieces of 1 mm × 1 mm to 5 mm × 5 mm, but the size of most of the disaggregation pieces is 1 mm × 1 mm or less.
Δ: There are mainly disaggregation pieces of 1 mm × 1 mm to 5 mm × 5 mm.
X: A disaggregation piece of 5 mm x 5 mm or more mainly exists.

<Undercoat layer (A) coating solution 3>
The following composition was mixed and the undercoat layer (A) coating liquid 3 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle size 4.3 μm, hollow rate 95%) ... 18.8 parts acrylic resin emulsion (Mitsui Chemicals) (Product name: Bonron S-1120, solid content: 43%) Agent (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.08 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 30.6 parts

<Undercoat layer (A) coating solution 4>
The following composition was mixed and the undercoat layer (A) coating liquid 4 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle size 4.3 μm, hollow ratio 95%)... 33.8 parts Acrylic resin emulsion (Mitsui Chemicals) (Product name: Bonron S-1120, solid content 43%) Agent (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.14 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 27.2 parts

<Undercoat layer (A) coating solution 5>
The following composition was mixed and the undercoat layer (A) coating liquid 5 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle size 4.3 μm, hollow ratio 95%) .... 13.0 parts Acrylic resin emulsion (Mitsui Chemicals) (Product name: Bonron S-1120, solid content: 43%) Agent (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.05 parts Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 31.9 parts

<Undercoat layer (A) coating solution 6>
The following composition was mixed and the undercoat layer (A) coating liquid 6 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 20%, volume average particle diameter 1.5 μm, hollow ratio 68%) ... 31.0 parts acrylic resin emulsion (Mitsui Chemicals, trade name: Bonron S-1120, solid content 43%) ... ..... 50.5 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.08 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 18.4 parts

<Undercoat layer (A) coating solution 7>
The following composition was mixed and the undercoat layer (A) coating liquid 7 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle size 9.8 μm, hollow ratio 85%) ... 18.8 parts acrylic resin emulsion (Mitsui Chemicals) (Product name: Bonron S-1120, solid content: 43%) Agent (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.08 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 30.6 parts

<Undercoat layer (A) coating solution 8>
The following composition was mixed and the undercoat layer (A) coating liquid 8 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle diameter 15.0 μm, hollow ratio 85%) ... 18.8 parts Acrylic resin emulsion (Mitsui Chemicals) Product name: Bonron S-1120, solid content concentration 43%) ... 50.5 parts Surfactant (Lion Corporation, trade name: Leocoal SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.08 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 30.6 parts

<Undercoat layer (A) coating liquid 9>
In 69.3 parts of water, 0.7 part of a polymer surfactant (trade name: Poise 520, solid concentration 40%) manufactured by Kao Corporation is dissolved, and anatase-type titanium oxide (Ishihara) is used as an inorganic pigment in this liquid. Sangyo Co., Ltd., product number: W-10) After adding 30 parts, it was processed with a bead mill to prepare a titanium oxide dispersion (1) having a solid content concentration of 30.3%. It was 0.16 micrometer when the average particle diameter of the titanium oxide dispersion liquid (1) was measured with the laser diffraction / scattering particle size distribution measuring apparatus (Horiba Ltd. make, product name: LA-720).
Next, the following composition was mixed and the undercoat layer (A) coating liquid 9 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle diameter 4.0 μm, hollow ratio 85%) ... 16.9 parts Acrylic resin emulsion (Mitsui Chemicals) Product name: Bonron S-1120, solid content concentration 43%) ... 45.5 parts Surface activity Agent (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.07 part Titanium oxide dispersion (1) prepared above・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 9.3 Parts Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・.... 28.2 parts

<Undercoat layer (A) coating solution 10>
In 69.3 parts of water, 0.7 part of a polymer surfactant (trade name: Poise 520, solid concentration 40%) manufactured by Kao Corporation is dissolved, and barium sulfate (Takehara Chemical Industries) is used as an inorganic pigment in this solution. Made by Co., Ltd., product number: W-1) After adding 30 parts, it was processed by a bead mill to prepare a barium sulfate dispersion (1) having a solid content concentration of 30.3%. The average particle size of the barium sulfate dispersion (1) was measured by a laser diffraction / scattering particle size distribution analyzer (manufactured by Horiba, Ltd., product name: LA-720) and found to be 1.0 μm.
Next, the following composition was mixed and the undercoat layer (A) coating liquid 10 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle diameter 4.0 μm, hollow ratio 85%) ... 16.9 parts Acrylic resin emulsion (Mitsui Chemicals) Product name: Bonron S-1120, solid content concentration 43%) ... 45.5 parts Surface activity Agent (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.07 parts Barium sulfate dispersion (1) prepared above ............ 9.3 parts Water ... ... 28.2 parts

<Undercoat layer (A) coating solution 11>
The following composition was mixed and the undercoat layer (A) coating liquid 11 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle size 4.1 μm, hollow ratio 85%) ... 18.8 parts ionomer emulsion (Mitsui Chemicals, Inc.) Made by company, trade name: Chemipearl SA-100, solid content concentration 35%) ... 62.0 parts Surfactant (Lion Corporation, trade name: Leocoal SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.08 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 19.1 parts

<Undercoat layer (A) coating liquid 12>
The following composition was mixed and the undercoat layer (A) coating liquid 12 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle diameter 4.1 μm, hollow ratio 85%) ... 18.8 parts acrylic resin emulsion (Mitsui Chemicals) Product name: Bonron S-416, solid content 45%) ... 48.3 parts Interface Activator (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.08 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 32.9 copies

<Undercoat layer (A) coating solution 13>
The following composition was mixed and the undercoat layer (A) coating liquid 13 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle size 4.0 μm, hollow rate 60%) ... 18.8 parts acrylic resin emulsion (Mitsui Chemicals) (Product name: Bonron S-1120, solid content: 43%) Agent (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.08 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 30.6 parts

<Undercoat layer (A) coating solution 14>
The following composition was mixed and the undercoat layer (A) coating liquid 14 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle diameter 4.0 μm, hollow ratio 40%) ... 18.8 parts acrylic resin emulsion (Mitsui Chemicals) (Product name: Bonron S-1120, solid content: 43%) Agent (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.08 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 30.6 parts

<Undercoat layer (A) coating solution 15>
The following composition was mixed and the undercoat layer (A) coating liquid 15 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle size 4.1 μm, hollow rate 85%) ... 38.3 parts Acrylic resin emulsion (Mitsui Chemicals) Manufactured by Co., Ltd., trade name: Bonron S-1120, solid content concentration 43%) ... 35.3 parts Agent (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.16 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 26.2 parts

<Undercoat layer (A) coating solution 16>
The following composition was mixed and the undercoat layer (A) coating liquid 16 was produced.
Hollow particles (acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer, solid content concentration 33%, volume average particle diameter 4.1 μm, hollow ratio 85%)... 12.1 parts acrylic resin emulsion (Mitsui Chemicals) Manufactured by Co., Ltd., trade name: Bonron S-1120, solid content concentration 43%) ... 55.7 parts Agent (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.05 parts Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 32.1 copies

<Undercoat layer (A) coating solution 17>
The following composition was mixed and the undercoat layer (A) coating liquid 17 was produced.
Styrene Butadiene Latex (manufactured by Nippon A & L Co., Ltd., trade name: Nalstar SR-102, glass transition temperature: 21 ° C., solid content concentration 48%) ... 58.2 parts Surfactant (Lion Corporation, (Product name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.08 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 41.8 parts

<Undercoat layer (A) coating liquid 18>
In 24.9 parts of water, 0.2 part of a polyacrylic acid-based dispersant (manufactured by Toagosei Co., Ltd., trade name: Aron T-50, solid content concentration 43%) is dissolved and kaolin (Imeris Minerals Japan Co., Ltd.) is dissolved. 100 parts of a product made by the company, trade name: Contour Xtreme) was added and dispersed to prepare a kaolin slurry. To this slurry, 28.8 parts of styrene butadiene latex (manufactured by Nippon Zeon Co., Ltd., trade name: LX-407S12, solid content concentration 48%) is added, and the undercoat layer (A) coating solution having a solid content concentration of 60% is added. 18 was prepared.
The outline of each of these undercoat layer (A) coating solutions is shown in the following table (however, the table shows only the mass ratio of the hollow particles, the binder resin, and the inorganic fine particles, and the brand of the resin emulsion of the binder) Names are omitted).

<< Undercoat layer (B) coating liquid >>
<Undercoat layer (B) coating solution 1>
The following composition was mixed and the undercoat layer (B) coating liquid 1 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 30%, volume average particle diameter 0.5 μm, hollow rate 55%) ... 40.5 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIKAFLEX 355HQ, solid content concentration 55%) ... 28.7 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.05 parts Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 30.7 parts

<Undercoat layer (B) coating solution 2>
The following composition was mixed and the undercoat layer (B) coating liquid 2 was produced.
Hollow particles (Styrene-acrylic copolymer, solid concentration 28.5%, volume average particle diameter 1.0 μm, hollow ratio 50%) ... 42.6 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIKAFLEX 355HQ, solid content concentration 55%) ... 28.7 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.05 parts Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 28.6 parts

<Undercoat layer (B) coating solution 3>
The following composition was mixed and the undercoat layer (B) coating liquid 3 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 20%, volume average particle diameter 0.3 μm, hollow ratio 50%) ... ... 60.8 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikaflex 355HQ, solid content concentration 55%) ... ... 28.7 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.05 parts Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 10.5 parts

<Undercoat layer (B) coating solution 4>
The following composition was mixed and the undercoat layer (B) coating liquid 4 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 30%, volume average particle diameter 0.5 μm, hollow rate 55%) ... ... 58.2 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikaflex 355HQ, solid content concentration 55%) ... ... 19.0 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.07 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 22.7 parts

<Undercoat layer (B) coating solution 5>
The following composition was mixed and the undercoat layer (B) coating liquid 5 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 30%, volume average particle diameter 0.5 μm, hollow rate 55%) ... 31.1 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikaflex 355HQ, solid content concentration 55%) ... 33.9 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.04 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 35.0 parts

<Undercoat layer (B) coating solution 6>
The following composition was mixed and the undercoat layer (B) coating liquid 6 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 37.5%, volume average particle diameter 0.5 μm, hollow rate 30%) ... 24.9 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIKAFLEX 355HQ, solid content concentration 55%) ... 33.9 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.04 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 41.2 parts

<Undercoat layer (B) coating solution 7>
The following composition was mixed and the undercoat layer (B) coating liquid 7 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 26.5%, volume average particle diameter 1.0 μm, hollow ratio 55%) ... 35.2 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIKAFLEX 355HQ, solid content concentration 55%) ... 33.9 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.04 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 30.9 parts

<Undercoat layer (B) coating solution 8>
The following composition was mixed and the undercoat layer (B) coating liquid 8 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 42.5%, volume average particle diameter 0.55 μm, hollow rate 20%) ... 21.9 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIKAFLEX 355HQ, solid content concentration 55%)・ ・ 33.9 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.04 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・... 44.1 parts

<Undercoat layer (B) coating solution 9>
The following composition was mixed and the undercoat layer (B) coating liquid 9 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 30%, volume average particle diameter 0.5 μm, hollow rate 55%) ... ... 33.9 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikaflex 355HQ, solid content concentration 55%) ... ... 26.4 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.04 part Boric acid ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Part 2.2 Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ 37.4 parts

<Undercoat layer (B) coating solution 10>
The following composition was mixed and the undercoat layer (B) coating liquid 10 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 30%, volume average particle diameter 0.5 μm, hollow rate 55%) ... ... 33.9 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikaflex 355HQ, solid content concentration 55%) ... ... 26.4 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.04 parts Adipic acid dihydrazide ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 2.2 parts Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・... 37.4 parts

<Undercoat layer (B) coating solution 11>
In 69.3 parts of water, 0.7 part of a polymer surfactant (trade name: Poise 520, solid concentration 40%) manufactured by Kao Corporation is dissolved, and anatase-type titanium oxide (Ishihara) is used as an inorganic pigment in this liquid. Sangyo Co., Ltd., product number: W-10) After adding 30 parts, it was processed with a bead mill to produce a titanium oxide dispersion (2) having a solid content concentration of 30.3%. It was 0.16 micrometer when the average particle diameter of the titanium oxide dispersion liquid (2) was measured with the laser diffraction / scattering particle size distribution measuring apparatus (Horiba Ltd. make, product name: LA-720). Next, the following composition was mixed and the undercoat layer (B) coating liquid 11 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 30%, volume average particle diameter 0.5 μm, hollow rate 55%) ... 32.6 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIKAFLEX 355HQ, solid content concentration 55%) ... 25.4 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.04 part Titanium oxide dispersion (2) produced above ... 10.8 parts Water ... ... 31.2 parts

<Undercoat layer (B) coating solution 12>
In 69.3 parts of water, 0.7 part of a polymer surfactant (trade name: Poise 520, solid concentration 40%) manufactured by Kao Corporation is dissolved, and barium sulfate (Takehara Chemical Industries) is used as an inorganic pigment in this solution. Product, product: W-1) After adding 30 parts, it processed with the bead mill, and produced barium sulfate dispersion (2) with a solid content concentration of 30.3%. The average particle size of the barium sulfate dispersion (2) was measured by a laser diffraction / scattering particle size distribution analyzer (manufactured by Horiba, Ltd., product name: LA-720) and found to be 1.0 μm. Next, the following composition was mixed and the undercoat layer (B) coating liquid 12 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 30%, volume average particle diameter 0.5 μm, hollow rate 55%) ... 32.6 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIKAFLEX 355HQ, solid content concentration 55%) ... 25.4 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.04 parts Barium sulfate dispersion (2) prepared above・ ・ ・ ・ ・ ・ ・ ・ ・ 10.8 parts Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・..31.2 parts

<Undercoat layer (B) coating solution 13>
The following composition was mixed and the undercoat layer (B) coating liquid 13 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 30%, volume average particle diameter 0.5 μm, hollow rate 55%) ... 40.5 parts acrylic resin emulsion (Mitsui Chemicals, trade name: Bonron S-1120, solid content 43%) ... 36.7 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.05 parts Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 22.7 parts

<Undercoat layer (B) coating solution 14>
The following composition was mixed and the undercoat layer (B) coating liquid 14 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 30%, volume average particle diameter 0.5 μm, hollow rate 55%) ... ... 40.5 parts Styrene butadiene latex (manufactured by Nippon A & L Co., Ltd., trade name: Nalstar SR-103, glass transition temperature: 7 ° C, solid content concentration 48%) ... 32. 9 parts Surfactant (Lion Corporation, trade name: Leocoal SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.05 parts Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・... 26.5 parts

<Undercoat layer (B) coating solution 15>
The following composition was mixed and the undercoat layer (B) coating liquid 15 was produced.
Dense particle emulsion (styrene-acrylic copolymer, solid content concentration 30%, volume average particle size 0.08 μm) ...・ ・ 40.5 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIKAFLEX 355HQ, solid concentration 55%) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・28.7 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.05 parts Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 30.7 parts

<Undercoat layer (B) coating solution 16>
The following composition was mixed and the undercoat layer (B) coating liquid 16 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 20%, volume average particle diameter 1.5 μm, hollow ratio 68%) ... ... 60.8 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikaflex 355HQ, solid content concentration 55%) ... ... 28.7 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.05 parts Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 10.5 parts

<Undercoat layer (B) coating solution 17>
The following composition was mixed and the undercoat layer (B) coating liquid 17 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 30%, volume average particle diameter 0.5 μm, hollow rate 55%) ... ... 66.5 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIKAFLEX 355HQ, solid concentration 55%) ... ... 14.5 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.08 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 18.9 parts

<Undercoat layer (B) coating liquid 18>
The following composition was mixed and the undercoat layer (B) coating liquid 18 was produced.
Hollow particles (styrene-acrylic copolymer, solid content concentration 30%, volume average particle diameter 0.5 μm, hollow rate 55%) ... 26.6 parts ethylene-vinyl acetate copolymer emulsion (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIKAFLEX 355HQ, solid content concentration 55%) ... 36.3 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.03 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 37.0 parts

<Undercoat layer (B) coating liquid 19>
In 69.3 parts of water, 0.7 part of a polymer surfactant (trade name: Poise 520, solid content concentration 40%, manufactured by Kao Corporation) was dissolved, and porous calcium carbonate (oil absorption 140 ml / ml) was dissolved in this container. 100 g) 9 parts and 21 parts of heavy calcium carbonate (oil absorption 50 ml / 100 g) were added, followed by stirring with a high-speed stirrer to prepare a calcium carbonate dispersion (1) having a solid content concentration of 30.3%.
Next, the following composition was mixed and the undercoat layer (B) coating liquid 19 was produced.
Calcium carbonate dispersion (1) prepared above: 71.6 parts Styrene butadiene latex (manufactured by Nippon A & L Co., Ltd., trade name: Nalstar SR-130, glass transition temperature) : -1 ° C, solid content concentration 49%) ··· 13.2 parts Surfactant (Lion Corporation, trade name: Leocol SC-50, active ingredient concentration 100%)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.06 part Water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 15.1 parts

<Undercoat layer (B) coating solution 20>
In 24.9 parts of water, 0.2 part of a polyacrylic acid-based dispersant (manufactured by Toagosei Co., Ltd., trade name: Aron T-50, solid content concentration 43%) is dissolved and kaolin (Imeris Minerals Japan Co., Ltd.) is dissolved. 46.1 parts by company, trade name: Contour Xtreme) were added and dispersed to prepare a kaolin slurry. To this slurry, 28.8 parts of styrene butadiene latex (manufactured by Nippon Zeon Co., Ltd., trade name: LX-407S12, solid concentration 48%) is added, and the undercoat layer (B) coating solution 20 having a solid concentration of 60% is added. Was prepared.
The outline of each of these undercoat layer (A) coating solutions is shown in the following table (however, the table shows only the mass ratio of the hollow particles, the binder resin, and the inorganic fine particles, and the brand of the resin emulsion of the binder) Names are omitted).

Next, preparation of the ink jet receiving layer coating solution will be described.
<Preparation of inorganic fine particle dispersion A>
In 39.22 parts of water, 0.78 part of polydiallyldimethylammonium chloride (trade name: Charol DC-902P, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., 51 mass% aqueous solution) was dissolved. (Product name: Aerosil 300, manufactured by Nippon Aerosil Co., Ltd.) 10 parts were dispersed.
This dispersion was processed using a high-pressure homogenizer to produce an inorganic fine particle dispersion having a solid content concentration of 20.8% and an average particle size of 0.20 μm.

<Preparation of ink receiving layer coating liquid A>
29.2 parts of water was added to 49.2 parts of the inorganic fine particle dispersion A prepared above, and 10% concentration of acetoacetyl group-modified polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: GOHSEFIMAR Z-) 410) 21.6 parts of an aqueous solution was mixed to prepare an ink-receiving layer coating liquid A having a solid concentration of 12% by mass.

<Preparation of ink receiving layer coating liquid B>
Water (30.6 parts) was added to the inorganic fine particle dispersion A (48 parts) prepared above to dissolve 0.29 parts of boric acid. This was mixed with 21.1 parts of an aqueous 10% concentration polyvinyl alcohol (trade name: PVA-235, manufactured by Kuraray Co., Ltd.) to prepare an ink-receiving layer coating solution B having a solid content concentration of 12% by mass.

[Example 1]
<Production of support>
5. Undercoat layer (A) coating liquid 1 is applied to the front and back surfaces of fine paper (manufactured by Nippon Paper Industries Co., Ltd., trade name: NIP quality, basis weight 180 g / m ² ), one side at a time, solid content coating amount per side. It apply | coated with the wire bar so that it might become 0 g / m < ² >, Then, the air of the temperature of 100 degreeC was sprayed and dried, and the undercoat layer (A) was formed. Next, on the undercoat layer (A) on each side, the undercoat layer (B) coating liquid 1 is applied with a wire bar so that the coating amount of the solid content per side is 9.0 g / m ² . Next, air at a temperature of 100 ° C. was blown and dried to form an undercoat layer (B). Next, in a state where the surface temperature of the surface side undercoat layer (B) is 25 ° C., the surface side undercoat layer (B) is brought into contact with the mirror surface metal roll of the calendar, so that the surface temperature of the calendar metal roll Calendering was performed at 55 ° C., 4 nips, linear pressure 200 kg / cm, and calendering speed 50 m / min to prepare a support.

<Preparation of inkjet recording material>
The ink receiving layer coating liquid A is applied to the surface of the undercoat layer on the surface of the support prepared as described above with a wire bar so that the solid content coating amount is 25 g / m ^2. Irradiated with an ultraviolet ray amount of which the integrated irradiation amount measured with −365 (manufactured by Eye Graphics Co., Ltd.) was 500 mJ / cm ² and then dried by blowing air at 120 ° C. to prepare an ink jet recording material.

[Example 2]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 2 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

[Example 3]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 3 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

[Example 4]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 4 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

[Example 5]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating solution 5 was used instead of the undercoat layer (A) coating solution 1 used in Example 1.

[Example 6]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating liquid 2 was used instead of the undercoat layer (B) coating liquid 1 used in Example 1.

[Example 7]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating liquid 3 was used instead of the undercoat layer (B) coating liquid 1 used in Example 1.

[Example 8]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating liquid 4 was used instead of the undercoat layer (B) coating liquid 1 used in Example 1.

[Example 9]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating solution 5 was used instead of the undercoat layer (B) coating solution 1 used in Example 1.

Next, various characteristics were evaluated about each produced inkjet recording material of Examples 1-9.
The results are shown in Table 3.

  From the results of Table 3, in the comparison of Examples 1 to 3 in which the hollow ratio of the hollow particles contained in the undercoat layer (A) is different, the higher the hollow ratio of the hollow particles, the higher the surface smoothness and the glossiness. It is clear that Moreover, in the comparison of Example 1, 4 and 5 in which the content of the binder contained in the undercoat layer (A) is different, compared to Example 4 and Example 1 in which the content of the binder is small compared to Example 1. In Example 5, where the binder content was large, the surface smoothness and gloss were slightly lower than in Example 1, but they had sufficient smoothness and gloss for photographic output. In Example 5, the cockling resistance was particularly good, and particularly excellent characteristics for photographic output were exhibited. As described above, the undercoat layer (A) contains hollow particles having a hollow ratio of 70% to 95% and a binder, and the mass of the binder contained in the undercoat layer (A) By being 150% or more and 550% or less of the mass of the hollow particles having a hollow ratio of 70% to 95% contained in A), an ink jet recording material having excellent surface smoothness, glossiness, and cockling resistance is obtained. Obviously.

In the comparison of Examples 1, 6 and 7 in which the average particle size of the hollow particles contained in the undercoat layer (B) is different, higher surface smoothness and glossiness can be obtained as the average particle size of the hollow particles is smaller. Is clear.
Moreover, in the comparison of Example 1, 8 and 9 in which the content of the binder contained in the undercoat layer (B) is different, Example 8 in which the content of the binder is smaller than that in Example 1, the content of the binder is large. In Example 9, both surface smoothness and gloss were slightly lower than Example 1, but they had sufficient smoothness and gloss for photographic output.
As described above, the undercoat layer (B) contains hollow particles having an average particle diameter of 0.3 μm or more and 1 μm or less and a binder, and the mass of the binder contained in the undercoat layer (B) is less than the undercoat layer (B 60% to 200% of the mass of the hollow particles having an average particle diameter of 0.1 μm or more and 1 μm or less, and the surface of the undercoat layer (B) is smoothed by calendering. It is clear that an ink jet recording material having good smoothness and glossiness can be obtained.

  The ink jet recording materials of Examples 1 to 9 had sufficient image density for use in photographic output. Moreover, about re-disaggregation, although it was a little difficult to disaggregate in Example 5, it was a level which has no problem in recyclability including the inkjet recording material of Examples 1-4 and Examples 6-9.

[Example 10]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 6 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

[Example 11]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 7 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

[Example 12]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 8 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

  Next, various characteristics were evaluated about each produced inkjet recording material of Examples 10-12. The results are shown in Table 4.

  In Example 2 in Table 3, the average particle diameter of the hollow particles contained in the undercoat layer (A) is smaller than that in Example 2, compared with Example 10, in Table 4, the average particle diameter of the hollow particles It is clear that higher surface smoothness and glossiness can be obtained with a smaller value. Moreover, in the comparison of Example 1 described in Table 3 and Examples 11 and 12 in which the average particle diameter of the hollow particles contained in the undercoat layer (A) is different from that in Example 1, the average particles of the hollow particles In Example 11 in which the diameter was 10 μm, it had sufficient smoothness and glossiness for photographic output, but in Example 12 in which the average particle diameter of the hollow particles was 15 μm, the smoothness and glossiness were somewhat. It is clear that the average particle size of the hollow particles contained in the undercoat layer (A) is particularly preferably 0.1 μm or more and 10 μm or less. Further, re-disaggregation was good in all the ink jet recording materials of Examples 10 to 12.

[Example 13]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating solution 6 was used instead of the undercoat layer (B) coating solution 1 used in Example 1.

[Example 14]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating solution 7 was used instead of the undercoat layer (B) coating solution 1 used in Example 1.

[Example 15]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating liquid 8 was used instead of the undercoat layer (B) coating liquid 1 used in Example 1.

  Next, various characteristics were evaluated about each produced inkjet recording material of Examples 13-15. The results are shown in Table 5.

  In comparison between Example 1 shown in Table 3 and Examples 13 and 15 in Table 5 in which the hollow ratio of the hollow particles contained in the undercoat layer (B) is lower than that in Example 1, the hollow particles were hollow. The rate was 30%. In Example 13, although the smoothness and gloss were slightly reduced as compared with Example 1, it had sufficient smoothness and gloss for photographic output. On the other hand, in Example 15 where the hollowness of the hollow particles is 25%, the smoothness and glossiness are lower, and the hollowness of the hollow particles contained in the undercoat layer (B) is more preferably 30% or more. Is clear. Moreover, in the comparison of Example 6 described in Table 3 and Example 14 in which the hollow ratio of the hollow particles contained in the undercoat layer (B) is higher than that of Example 6, the hollow ratio of the hollow particles is higher. It is clear that the higher the value, the better the smoothness and glossiness. Further, re-disintegration was good in all the ink jet recording materials of Examples 13 to 15.

[Example 16]
<Production of support>
5. Undercoat layer (A) coating liquid 1 is applied to the front and back surfaces of fine paper (manufactured by Nippon Paper Industries Co., Ltd., trade name: NIP quality, basis weight 180 g / m ² ), one side at a time, solid content coating amount per side. It apply | coated with the wire bar so that it might become 0 g / m < ² >, Then, the air of temperature 100 degreeC was sprayed and dried, and the undercoat layer (A) was formed. Next, the undercoat layer (B) coating liquid 1 is applied on the undercoat layer (A) with a wire bar so that the coating amount of the solid content per side is 9.0 g / m ² on each side, and then the temperature is 100. Drying was performed by blowing air at 0 ° C. to form an undercoat layer (B). Next, in a state where the surface temperature of the undercoat layer (B) is 25 ° C., the surface temperature of the calender metal roll is 55 ° C., 4 nips so that the undercoat layer (B) is in contact with the mirror surface metal roll of the calender. Calendering was performed under the conditions of a linear pressure of 200 kg / cm and a calendering speed of 50 m / min to prepare a support.

<Preparation of inkjet recording material>
The ink receiving layer coating solution B is applied to the surface of the undercoat layer on the surface of the support prepared above with a wire bar so that the solid content coating amount is 25 g / m ² , and first, air at 5 ° C. is sprayed for 3 minutes. After the coating layer was cooled, air at a temperature of 40 ° C. and a relative humidity of 20% was blown for 20 minutes to dry, thereby producing an ink jet recording material.

[Example 17]
<Production of support>
5. Undercoat layer (A) coating liquid 1 is applied to the front and back surfaces of fine paper (manufactured by Nippon Paper Industries Co., Ltd., trade name: NIP quality, basis weight 180 g / m ² ), one side at a time, solid content coating amount per side. It apply | coated with the wire bar so that it might become 0 g / m < ² >, Then, the air of temperature 100 degreeC was sprayed and dried, and the undercoat layer (A) was formed. Next, on the undercoat layer (A), the undercoat layer (B) coating liquid 9 is applied with a wire bar so that the coating amount of the solid content per side is 9.0 g / m ² , and then the temperature is 100. Drying was performed by blowing air at 0 ° C. to form an undercoat layer (B). Next, with the surface temperature of the undercoat layer (B) being 25 ° C., the surface side undercoat layer (B) is in contact with the mirror surface metal roll of the calendar, so that the surface temperature of the calendar metal roll is 55 ° C., Calendering was performed under conditions of 4 nips, linear pressure 200 kg / cm, and calendering speed 50 m / min to prepare a support.

<Preparation of inkjet recording material>
The ink receiving layer coating solution B is applied to the surface of the undercoat layer on the surface of the support prepared above with a wire bar so that the solid content coating amount is 25 g / m ² , and first, air at 5 ° C. is sprayed for 3 minutes. After the coating layer was cooled, air at a temperature of 40 ° C. and a relative humidity of 20% was blown for 20 minutes to dry, thereby producing an ink jet recording material.

[Example 18]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating solution 10 was used instead of the undercoat layer (B) coating solution 1 used in Example 1.

[Example 19]
<Production of support>
5. Undercoat layer (A) coating liquid 1 is applied to the front and back surfaces of fine paper (manufactured by Nippon Paper Industries Co., Ltd., trade name: NIP quality, basis weight 180 g / m ² ), one side at a time, solid content coating amount per side. It apply | coated with the wire bar so that it might become 0 g / m < ² >, Then, the air of temperature 100 degreeC was sprayed and dried, and the undercoat layer (A) was formed. Next, on the undercoat layer (A), the undercoat layer (B) coating liquid 10 is applied with a wire bar so that the coating amount of the solid content per side is 9.0 g / m ² , and then the temperature is 100. Drying was performed by blowing air at 0 ° C. to form an undercoat layer (B). Next, with the surface temperature of the undercoat layer (B) on the surface side being 25 ° C., the surface temperature of the calender metal roll is 55 ° C. so that the undercoat layer (B) is in contact with the mirror surface metal roll of the calender. Calendering was performed under conditions of 4 nips, linear pressure 200 kg / cm, and calendering speed 50 m / min to prepare a support.

<Preparation of inkjet recording material>
The ink receiving layer coating liquid A is applied to the surface of the undercoat layer on the surface of the support prepared above with a wire bar so that the solid content is 25 g / m ² , and air at a temperature of 120 ° C. is blown for 5 minutes. It dried and produced the inkjet recording material.

  Next, various characteristics were evaluated about each produced inkjet recording material of Examples 16-19. The results are shown in Table 6.

  In comparison between Example 16 in which the undercoat layer (B) does not contain a crosslinking agent and Example 17 in which boric acid is added as a crosslinking agent to the undercoat layer (B), Example 17 has a higher surface smoothness. And glossiness were obtained. Also in Example 18 in which adipic acid dihydrazide was added as a crosslinking agent to the undercoat layer (B) of Example 1, the surface smoothness and glossiness were improved as compared with Example 1. Further, in Example 19 where ultraviolet irradiation was not performed in the ink receiving layer forming step in Example 18, the same surface smoothness and gloss as in Example 18 were obtained. As described above, it is apparent that the smoothness and glossiness of the surface are improved by adding a crosslinking agent to the undercoat layer (B). Further, re-disintegration was good in all the ink jet recording materials of Examples 16 to 19.

[Example 20]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 9 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

[Example 21]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating solution 10 was used instead of the undercoat layer (A) coating solution 1 used in Example 1.

[Example 22]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating solution 11 was used instead of the undercoat layer (B) coating solution 1 used in Example 1.

[Example 23]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating liquid 12 was used instead of the undercoat layer (B) coating liquid 1 used in Example 1.

  Next, various characteristics were evaluated about each produced inkjet recording material of Examples 20-23. The results are shown in Table 7.

  In Examples 20 and 21 in which an inorganic pigment was added to the undercoat layer (A), no significant reduction in surface smoothness or gloss was observed as compared with Example 1 described in Table 3. However, in Examples 21 and 22 in which the inorganic pigment was added to the undercoat layer (B), the surface smoothness and glossiness decreased greatly. From the above, it is clear that by adding an inorganic pigment to the undercoat layer (A), it is possible to add the inorganic pigment without reducing the smoothness of the surface or reducing the glossiness. Further, re-disintegration was good in all the ink jet recording materials of Examples 20 to 23.

[Example 24]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 11 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

[Example 25]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 12 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

[Example 26]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating solution 13 was used instead of the undercoat layer (B) coating solution 1 used in Example 1.

[Example 27]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating solution 14 was used instead of the undercoat layer (B) coating solution 1 used in Example 1.

  Next, various characteristics were evaluated about each inkjet recording material of produced Examples 24-27. The results are shown in Table 8.

  Similarly to Example 1, in Examples 24 and 25 in which the binder type of the undercoat layer (A) was changed with respect to Example 1, and in Examples 26 and 27 in which the binder type of the undercoat layer (B) was changed, It exhibited high surface smoothness and glossiness, and was an excellent characteristic as an inkjet recording material for photographic output. In particular, Example 24 using an ionomer emulsion as a binder for the undercoat layer (A) showed very high cockling resistance and was particularly excellent as an inkjet recording material for photographic output. Regarding re-disintegration, Example 24 was a little difficult to disaggregate, but all of the ink-jet recording materials of Examples 25 to 27 were at a level with no problem in recyclability.

[Example 28]
In Example 1, instead of calendering under the condition that the surface temperature of the calender metal roll was 55 ° C., the ink jet was performed under the same conditions as in the example except that the calendering was performed under the condition that the surface temperature of the calender metal roll was 45 ° C. A recording material was prepared.

[Example 29]
In Example 1, instead of calendering under the condition that the surface temperature of the calender metal roll was 55 ° C, the ink jet was performed under the same conditions as in the example except that the calendering was performed under the condition that the surface temperature of the calender metal roll was 80 ° C. A recording material was prepared.

[Example 30]
In Example 1, instead of calendering under the condition that the surface temperature of the calender metal roll was 55 ° C, the ink jet was performed under the same conditions as in the example except that the calendering was performed under the condition that the surface temperature of the calender metal roll was 30 ° C. A recording material was prepared.

[Example 31]
In Example 1, instead of calendering under the condition that the surface temperature of the calender metal roll was 55 ° C, the ink jet was carried out under the same conditions as in the example except that the calendering was performed under the condition that the surface temperature of the calender metal roll was 100 ° C. A recording material was prepared.

  Next, various characteristics of each of the produced inkjet recording materials of Examples 28 to 31 were evaluated. The results are shown in Table 9.

  In the comparison between Example 1 and Examples 28 to 31 in which the surface temperature of the calendar treatment was changed with respect to Example 1, in Examples 1, 28 and 29 where the surface temperature was 45 ° C. to 80 ° C., the surface temperature The smoothness and glossiness were high, but in Example 30 where the surface temperature was 30 ° C. and Example 31 where the surface temperature was 100 ° C., the smoothness and glossiness of the surface were low, and the calendar treatment It is clear that the surface temperature is preferably 45 ° C to 80 ° C. Further, the re-disintegration property was at a level where there was no problem in the recyclability of all the inkjet recording materials of Examples 28 to 31.

[Example 32]
In Example 1, instead of setting the solid content coating amount of the undercoat layer (A) coating liquid 1 to 6.0 g / m ² , the same procedure as in Example 1 was performed except that the solid content coating amount was 3.0 g / m ^2. An ink jet recording material was produced under the same conditions.

[Example 33]
In Example 1, instead of changing the solid coating amount of the undercoat layer (A) coating liquid 1 to 6.0 g / m ² , the coating amount of Example 1 was changed to 15.0 g / m ^2. An ink jet recording material was produced under the same conditions.

[Example 34]
In Example 1, instead of changing the solid coating amount of the undercoat layer (B) coating liquid 1 to 9.0 g / m ² , except that the solid coating amount was 6.0 g / m ² , Example 1 and An ink jet recording material was produced under the same conditions.

[Example 35]
In Example 1, instead of changing the solid coating amount of the undercoat layer (B) coating liquid 1 to 9.0 g / m ² , except that the solid coating amount was 20.0 g / m ² , An ink jet recording material was produced under the same conditions.

  Next, various characteristics were evaluated about each inkjet recording material of produced Examples 32-35. The results are shown in Table 10.

In the comparison between Example 1 and Examples 32 to 35 in which the coating amount of the undercoat layer (A) or (B) was changed with respect to Example 1, the coating amount of the undercoat layer (A) was reduced. In Example 32 and Example 34 in which the coating amount of the undercoat layer (B) was reduced, the surface smoothness and glossiness were slightly lowered, but the characteristics were sufficient for photographic output. Further, in Example 32 in which the coating amount of the undercoat layer (A) was reduced, the cockling resistance was slightly lowered.
In Example 33 in which the coating amount of the undercoat layer (A) was increased, the surface smoothness and cockling resistance were improved, and the characteristics became more preferable for photographic output. In Example 35 in which the coating amount of the undercoat layer (B) was increased, the surface smoothness, the 20 ° glossiness, and the cockling resistance were improved and became more preferable characteristics for photographic output. Regarding re-disaggregation, Examples 33 and 35 were a little difficult to disaggregate, but all of them including the ink-jet recording materials of Examples 32 and 35 were at a level with no problem in recyclability.

[Comparative Example 1]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 13 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

[Comparative Example 2]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 14 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

[Comparative Example 3]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating solution 15 was used instead of the undercoat layer (B) coating solution 1 used in Example 1.

[Comparative Example 4]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating liquid 16 was used instead of the undercoat layer (B) coating liquid 1 used in Example 1.

[Comparative Example 5]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 15 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

[Comparative Example 6]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (A) coating liquid 16 was used instead of the undercoat layer (A) coating liquid 1 used in Example 1.

[Comparative Example 7]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating liquid 17 was used instead of the undercoat layer (B) coating liquid 1 used in Example 1.

[Comparative Example 8]
An ink jet recording material was obtained under the same conditions as in Example 1 except that the undercoat layer (B) coating liquid 18 was used instead of the undercoat layer (B) coating liquid 1 used in Example 1.

[Comparative Example 9]
<Production of support>
7. Undercoat layer (A) coating liquid 17 is applied to the front and back surfaces of high-quality paper (Nippon Paper Industries Co., Ltd., trade name: NIP quality, basis weight 180 g / m ² ). It apply | coated with the wire bar so that it might become 0 g / m < ² >, Then, the air of temperature 100 degreeC was sprayed and dried, and the undercoat layer (A) was formed. Next, on the undercoat layer (A), the undercoat layer (B) coating liquid 19 is applied with a wire bar so that the coating amount of the solid content per side is 10.0 g / m ² on one side, and then the temperature is 100. Drying was performed by blowing air at 0 ° C. to form an undercoat layer (B). Next, with the surface temperature of the undercoat layer (B) on the surface side being 25 ° C., the surface temperature of the calender metal roll is 55 ° C. so that the undercoat layer (B) is in contact with the mirror surface metal roll of the calender. Calendering was performed under conditions of 4 nips, linear pressure 200 kg / cm, and calendering speed 50 m / min to prepare a support.

<Preparation of inkjet recording material>
The ink receiving layer coating liquid A is applied to the surface of the undercoat layer on the surface of the support prepared as described above with a wire bar so that the solid content coating amount is 25 g / m ^2. Irradiated with an ultraviolet ray amount of which the integrated irradiation amount measured with −365 (manufactured by Eye Graphics Co., Ltd.) was 500 mJ / cm ² and then dried by blowing air at 120 ° C. to prepare an ink jet recording material.

[Comparative Example 10]
<Production of support>
The undercoat layer (A) coating liquid 18 is applied to the front and back surfaces of high-quality paper (manufactured by Nippon Paper Industries Co., Ltd., trade name: NIP quality, basis weight 180 g / m ² ), one side at a time, solid content coating amount per side 12. It apply | coated with the wire bar so that it might become 0 g / m < ² >, Then, the air of temperature 100 degreeC was sprayed and dried, and the undercoat layer (A) was formed. Next, on the undercoat layer (A), the undercoat layer (B) coating liquid 20 is applied with a wire bar so that the coating amount of the solid content per side is 10.0 g / m ² , and then the temperature is 100. Drying was performed by blowing air at 0 ° C. to form an undercoat layer (B). Next, with the surface temperature of the undercoat layer (B) on the surface side being 25 ° C., the surface temperature of the calender metal roll is 55 ° C. so that the undercoat layer (B) is in contact with the mirror surface metal roll of the calender. Calendering was performed under conditions of 4 nips, linear pressure 200 kg / cm, and calendering speed 50 m / min to prepare a support.

<Preparation of inkjet recording material>
The ink receiving layer coating liquid A is applied to the surface of the undercoat layer on the surface of the support prepared as described above with a wire bar so that the solid content coating amount is 25 g / m ^2. Irradiated with an ultraviolet ray amount of which the integrated irradiation amount measured with −365 (manufactured by Eye Graphics Co., Ltd.) was 500 mJ / cm ² and then dried by blowing air at 120 ° C. to prepare an ink jet recording material.

[Comparative Example 11]
<Production of support>
10% by mass of 100% by mass of low density polyethylene resin having a density of 0.919 g / cm ^{3 on} the surface of fine paper (made by Nippon Paper Industries Co., Ltd., trade name: NIP quality, basis weight 180 g / m ² ) A polyethylene resin composition in which anatase-type titanium oxide was uniformly dispersed was melted at 320 ° C., extrusion-coated to a thickness of 20 μm, and extrusion-coated using a mirror-finished cooling roll.
On the other surface which is the back surface, a blend resin composition of 65 parts by mass of a high density polyethylene resin having a density of 0.954 g / cm ³ and 35 parts by mass of a low density polyethylene resin having a density of 0.924 was melted at 320 ° C. The film was extrusion-coated to a thickness of 30 μm and extrusion-coated using a cooling roll having a rough surface.
Thereafter, the resin surface was subjected to high frequency corona discharge treatment to prepare a resin-coated paper support.

<Preparation of inkjet recording material>
The ink receiving layer coating liquid A was applied to the surface of the support produced above by extrusion coating using a mirror-finished cooling roll with a wire bar so that the solid content was 25 g / m ^2. In the inkjet recording material, an ultraviolet ray amount measured by an ultraviolet ray illuminance meter PD-365 (manufactured by Eye Graphics Co., Ltd.) is irradiated with an ultraviolet ray amount of 500 mJ / cm ² and then dried by blowing air at 120 ° C. Was made.

  Next, various characteristics were evaluated about each inkjet recording material of the produced comparative examples 1-11. The results are shown in Table 11.

In Comparative Examples 1 and 2 in which the hollow percentage of the hollow particles contained in the undercoat layer (A) is less than 70%, the surface smoothness and glossiness are lower than in Example 1, and are not suitable for photographic output. It was enough.
Comparative Example 3 containing fine dense resin particles instead of hollow particles in the undercoat layer (B), and Comparative Example 4 containing hollow particles having an average particle diameter exceeding 1 μm in the undercoat layer (B). Also, the surface smoothness and glossiness were low, which was insufficient for photographic output.
In Comparative Example 5 in which the mass of the binder contained in the undercoat layer (A) is less than 150% with respect to the mass of the hollow particles having a hollow ratio of 70% or more and 95% or less, the surface smoothness and gloss In addition, the degree of cockling resistance was very poor and it was not suitable for photographic output.
In Comparative Example 6 in which the mass of the binder contained in the undercoat layer (A) exceeds 550% with respect to the mass of the hollow particles having a hollow ratio of 70% or more and 95% or less, the cockling resistance is very good. However, the surface smoothness and glossiness were low, which was insufficient for photographic output.
In any of Comparative Example 7 where the mass of the binder contained in the undercoat layer (B) is less than 60% with respect to the mass of the hollow particles having an average particle diameter of 0.3 μm or more and 1 μm or less, and Comparative Example 8 exceeding 200%. However, the smoothness and glossiness of the surface were low, which was insufficient for photographic output.
Further, in Comparative Examples 9 and 10 containing no inorganic particles in the undercoat layer (A) and / or the undercoat layer (B), the cockling resistance was good, The smoothness and glossiness of the surface were low, which was insufficient for photographic output.
Regarding re-disaggregation, Comparative Examples 6, 9 and 10 were slightly difficult to disaggregate, but were at a level where there was no problem in recyclability.
Comparative Examples 1 to 5 and Comparative Examples 7 and 8 had good re-dissociation properties. In Comparative Example 11 using the resin-coated paper support, the surface smoothness, glossiness and cockling resistance were all excellent, but re-disaggregation was difficult and the recyclability was poor.

JP 2004-167959 A JP 2005-199550 A JP-A-2005-2225070 JP 2007-290339 A JP 2002-321449 A JP 2004-291520 A JP 2005-238829 A JP 2007-160758 A JP 2010-30231 A JP 2002-059637 A JP 2003-127530 A

Claims (7)

  An ink jet recording material having an ink receiving layer provided on a support has an undercoat composed of a plurality of layers between the support and the ink receiving layer, and is the farthest from the support constituting the undercoat. Any undercoat layer (A) excluding the layer contains hollow particles having a higher hollow ratio and a binder, and is adjacent to the side of the undercoat layer (A) opposite to the support. (B) contains hollow particles having a lower hollow ratio and a smaller average particle size and a binder, and the surface of the undercoat layer (B) is smoothed by calendaring, In the undercoat layer (A), the mass ratio of the binder to the amount of hollow particles having a higher hollow ratio is such that the amount of the binder to the amount of hollow particles in the undercoat layer (B). The hollow particles in the undercoat layer (A) are deformed so as to flatten the undercoat layer (A) by filling the unevenness of the support by the calendering process. An ink jet recording material characterized by being made easy.   The hollow particles in the undercoat layer (A) have a hollow ratio of 70% to 95%, and the mass of the binder contained in the undercoat layer (A) is in the undercoat layer (A). The hollow particles contained in the undercoat layer (B) that is 150% or more and 550% or less of the mass of the contained hollow particles and is adjacent to the opposite side of the support of the undercoat layer (A). However, the average particle size is 0.3 μm or more and 1 μm or less, and the mass of the binder contained in the undercoat layer (B) is 0.3 μm or more in average particle size contained in the undercoat layer (B). 2. The inkjet recording material according to claim 1, which is 60% or more and 200% or less of a mass of hollow particles of 1 μm or less.   The inkjet recording material according to claim 1 or 2, wherein the hollow particles contained in the undercoat layer (A) have an average particle diameter of 1 µm or more and 10 µm or less.   The ink jet recording material according to claim 2 or 3, wherein the hollow ratio of hollow particles having an average particle diameter of 0.3 µm to 1 µm contained in the undercoat layer (B) is 30% to 80%.   The undercoat layer (B) contains a crosslinking agent that gels the binder of the ink receiving layer, and the ink receiving layer is configured to be adjacent to the undercoat layer (B). The inkjet recording material as described in any one.   The inkjet recording material according to any one of claims 1 to 5, wherein the undercoat layer (A) contains an inorganic pigment having an average particle size of 0.1 µm or more and an average particle size of 1 µm or less.   The smoothing of the surface of the undercoat layer (B) by calendering is performed by calendering a mirror roll having a surface temperature of 45 ° to 80 ° so as to contact the surface of the undercoat layer (B). The ink jet recording material according to claim 6.