JP2010284881A - Recording sheet with ink receiving layer, and coating liquid for ink receiving layer formation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording sheet with an ink receiving layer which excels in such properties as ink absorbency and gas barrier properties, and also to provide coating liquid for ink receiving layer formation which can produce this recording sheet. <P>SOLUTION: The coating liquid for ink receiving layer formation consists of swellable resin particles having a core cell structure with cell layer of swellable resin, polymerizable unsaturated monomer, polymer resin, a crosslinking agent, inorganic fine particles, and a dispersion medium, wherein the average primary particle diameter of the inorganic fine particle measured by the TEM method is in the range of 1-200 nm; pore volume (PV<SB>N</SB>) measured by the nitrogen adsorption method is in the range of 0.1-2.0 cc/g; the average pore diameter is in the range of 5-60 nm; total solid content density is in the range of 1-50 wt.%; the density of swellable resin particle is in the range of 0.05-40 wt.% as a solid content; the density of polymerizable unsaturated monomers is in the range of 0.01-20 wt.% as a solid content; the density of polymer resin is in the range of 0.01-10 wt.% as a solid content; the density of crosslinking agent is in the range of 0.001-10 wt.% as a solid content; the density of inorganic fine particle is in the range of 0.01-45 wt.% as a solid content. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a novel ink-receiving layer-forming coating solution and a recording sheet with an ink-receiving layer using the coating solution. Specifically, the components used in the ink receiving layer are cross-linked with each other to have a network structure, and have a recording sheet with an ink receiving layer excellent in ink absorbability, gas barrier properties, etc., and ink receiving that can provide the sheet The present invention relates to a layer forming coating solution.

  The ink jet recording method employs a method of recording images, characters, etc. by spraying fine droplets of pigment or dye ink onto a recording medium such as paper or PET film. Is popular. Furthermore, images recorded by the multi-color inkjet method can obtain a recording that is comparable to multi-color printing by the plate-making method and printing by the color photographic method. Since it is cheaper than multi-color printing or printing, it has been widely applied for full-color image recording. Therefore, high-speed recording, high definition, and full color are possible, and ink absorbency, color reproducibility to cope with improvement in recording characteristics such as light resistance, water resistance, kill resistance, gas barrier properties, fixing, Development of recording media excellent in saturation, image clarity, and the like has been underway.

As an ink receiving layer, Japanese Patent Application Laid-Open No. 7-232475 (Patent Document 1) uses alumina hydrate, and has an average pore radius of 20 to 200 mm and a half-width of pore diameter distribution of 20 to 150 mm. A layer is disclosed. Japanese Patent Application Laid-Open No. 8-310115 (Patent Document 2) discloses a recording medium having an ink receiving layer containing alumina hydrate and a water-soluble polymer, wherein the primary particles of alumina hydrate are aggregated by anions. An ink-receiving layer comprising an aggregate structure and a water-soluble polymer is disclosed. In JP-A-6-199034 (Patent Document 3), an alumina hydrate porous material having a mean pore radius of 30 to 80 mm formed from boehmite sol having a secondary aggregated particle diameter of 100 to 160 nm is formed on a substrate. An alumina hydrate porous layer having an average pore radius of 50 to 100 mm formed from boehmite sol having a secondary aggregated particle diameter of 300 to 500 nm is formed on the upper layer of the porous layer having a thickness of 5 to 40 μm. A recording sheet having a thickness of ˜20 μm is disclosed.

Japanese Patent Laid-Open No. 2004-255689 (Patent Document 4) discloses an inkjet recording material in which at least two ink-receiving layers containing inorganic fine particles and a hydrophilic binder are coated on a support. The near ink receiving layer A mainly contains fine particles obtained by pulverizing wet-process silica in an aqueous medium to an average secondary particle diameter of 500 nm or less, and the ink receiving layer B separated from the support contains alumina hydrate fine powder in the aqueous medium. Among them, an inkjet recording material mainly containing alumina hydrate peptized with an organic acid without containing an inorganic acid is disclosed.

JP 2002-240243 (Patent Document 5) discloses that a porous film is formed of a binder and inorganic fine particles, an acrylic resin or urethane resin is used for the binder, and silica is used for the inorganic fine particles. Alternatively, a recording medium using titanium oxide is disclosed.

  JP-A-2006-88341 (Patent Document 6) discloses a cationic acrylic silicon emulsion resin and a cationic resin as an ink jet recording sheet that is particularly excellent in the absorbability, drying property, and coloring property of aqueous pigment inks. Those containing urethane resins have been proposed.

Further, JP-A-11-301098 (Patent Document 7) discloses that a water-absorbing layer composed of water-absorbing resin fine particles and a hydrophobic binder resin on a support, a cation-modified acrylic copolymer and a polyvinyl acetal resin are epoxy. An ink jet recording medium is disclosed in which an ink receiving layer made of a resin thermally cured with a compound is laminated in this order.

Japanese Unexamined Patent Publication No. 7-232475 JP-A-8-310115 JP-A-6-199034 JP 2004-255689 A JP 2002-240243 A JP 2006-088341 A JP 11-301098 A

  However, the ink receiving layer containing conventional inorganic fine particles such as Patent Documents 1 to 5 as a filler and a resin as a binder (hereinafter sometimes referred to as a matrix) has the following problems.

(1) Since inorganic fine particle fillers and binders having different refractive indexes form nanopores, saturation, brightness, etc. are insufficient due to light scattering, diffraction, interference, and haze increases. (2) Even after the ink is absorbed and dried, the pores of the nanopores are present and discolored due to environmental gases, etc., that is, the gas barrier property is inferior. (3) Insufficient crosslinking of the binder resin For this reason, cracks may occur or the adhesion to the substrate may be insufficient. (4) Depending on the type of dye or pigment, there are problems such as fixing properties.

  For example, a coating layer using alumina hydrate particles has a narrow pore size distribution with an average pore size of 10 to 30 angstroms. There is a drawback in that the absorbability of the solvent is insufficient and bleeding occurs. In addition, pigment inks are not suitable for printing pigment inks because they cannot absorb or fix pigments.

  Generally, reducing the particle size of the particles to be introduced into the ink receiving layer may improve the transparency and smoothness of the ink receiving layer. However, when the particles are packed closely, large pores are not formed. However, there was a drawback that the ink absorbability deteriorated although the scratch resistance was high. On the other hand, when the particle size is large, the pore size is large and the ink absorbency is high, but the transparency of the ink receiving layer, haze, smoothness, adhesion between the recording medium and the ink receiving layer, the strength of the ink demand layer, There is a drawback that scratch resistance and the like deteriorate.

  In addition, in the case of Patent Document 6, there is a problem that, since the swelling property is insufficient, pores sufficient to penetrate the ink are not formed, and cracks are generated when the ink swells due to low elasticity. It was.

  Further, Patent Document 7 discloses that even when ink is provided on a non-water-absorbing support such as a plastic film, the ink absorption of the conventional ink receiving layer is insufficient, so that the water absorption between the support and the ink receiving layer is insufficient. The recording medium is provided with a water-absorbing layer composed of fine resin particles and a hydrophobic binder, and has a wettability and dyeability of ink, and particularly provides a recording medium excellent in transparency. However, it is clearly different from the technical idea of providing a specific cross-linked structure in the ink receiving layer as in the present invention.

As a result of intensive investigations in view of the above problems, the present inventors have found that as particles dispersed in the ink receiving layer, resin fine particles having a core-cell structure, polymerizable unsaturated monomers and polymer resins constituting a matrix, and a crosslinking agent In addition, by containing inorganic fine particles having specific pore characteristics, the ink absorption speed is fast, the dye can penetrate and fix inside the ink receiving layer, and the pigment can fix on the surface of the ink receiving layer. Swelling disappears and shrinks as the dispersion medium evaporates, and has excellent scratch resistance, transparency, gas barrier properties, etc., high-speed recording, high definition, full color, excellent image clarity, etc. The inventors have found that a recording sheet with an ink receiving layer can be obtained, and have completed the present invention.

[1] A swellable resin particle having a core cell structure having a cell layer made of a swellable resin, a polymerizable unsaturated monomer, a polymer resin, a crosslinking agent, inorganic fine particles, and a dispersion medium,
The average primary particle diameter measured by the TEM observation method of the inorganic fine particles is in the range of 1 to 200 nm, and the pore volume (PV _N ) measured by the nitrogen adsorption method is in the range of 0.1 to 2.0 cc / g. The average pore diameter is in the range of 5 to 60 nm, the total solid content concentration is in the range of 1 to 50% by weight,
The concentration of the swellable resin particles is in the range of 0.05 to 40% by weight as the solid content,
The concentration of the polymerizable unsaturated monomers is in the range of 0.01 to 20% by weight as a solid content,
The concentration of the polymer resin is in the range of 0.01 to 10% by weight as the solid content,
The concentration of the crosslinking agent is in the range of 0.001 to 10% by weight as a solid content,
A coating liquid for forming an ink receiving layer, wherein the concentration of the inorganic fine particles is in the range of 0.01 to 45% by weight as the solid content.

[2] The inorganic fine particles are at least one selected from the group consisting of MgO, TiO ₂ , SiO ₂ , ZrO ₂ , Al ₂ O ₃ , Sb ₂ O ₅ , ZnO and complex oxides thereof, The coating solution for forming an ink receiving layer according to [1], wherein the average particle diameter measured by a scattering method is in the range of 5 to 10,000 nm.

  [3] The ink receiving layer forming coating solution according to [1] or [2], wherein the inorganic fine particles are pseudo boehmite alumina and / or boehmite alumina.

  [4] The coating solution for forming an ink receiving layer according to [1] to [3], wherein the inorganic fine particles have a chain structure.

[5] The coating solution for forming an ink receiving layer according to [1] to [4], wherein the swellable resin particles have an average particle diameter in the range of 20 to 500 nm.

[6] Coating for forming an ink receiving layer according to [1] to [5], wherein the core of the swellable resin particles is made of one or more resins selected from acrylic resin fine particles, urethane resin fine particles, and vinyl resin fine particles. liquid.

[7] The coating solution for forming an ink receiving layer according to [1] to [6], wherein the swellable resin constituting the cell layer of the swellable resin particles includes a polymer main chain derived from a (meth) acrylic resin.

[8] The swelling resin constituting the cell layer has a carboxyl group, a carbonyl group, a hydroxyl group, an amino group, a halogen group, a urethane group, an alkyl group, a phenyl group, a sulfone group, an alkoxyl group, a thiol at a side chain or a terminal. A coating solution for forming an ink receiving layer according to any one of [1] to [7], which contains at least one functional group selected from the group consisting of a group and a cyano group.

[9] The coating solution for forming an ink receiving layer according to [1] to [8], wherein the crosslinking agent is at least one selected from carbodiimide compounds, cyano compounds, melamine compounds, oxozaline compounds, and isocyanate compounds.

[10] (i) The polymerizable unsaturated monomer comprises a carboxyl group, a carbonyl group, a hydroxyl group, an amino group, a halogen group, a urethane group, an alkyl group, a phenyl group, a sulfone group, an alkoxyl group, a vinyl group, or a thiol group. (Meth) acrylic resin having at least one functional group selected from the group, organic acid vinyl ester resin, vinyl ether resin, halogen-containing resin, ester resin, amide resin, urethane resin, cellulose derivative,
(ii) The group in which the polymer resin is composed of acrylic resin fine particles, urethane resin fine particles, polyvinyl alcohol resin fine particles, vinyl resin fine particles, ethylene resin fine particles, polystyrene resin fine particles, ester resin fine particles, and epoxy resin fine particles. A coating solution for forming an ink receiving layer according to any one of [1] to [9], which is at least one selected from

[11] comprising a base sheet and an ink receiving layer formed on the base sheet,
The ink receiving layer is composed of swellable resin particles having a core cell structure, a resin matrix and inorganic fine particles,
The cell layer of the swellable resin particles is made of a swellable resin,
The swelling resin of the cell layer and the resin matrix have a crosslinked network structure,
The average primary particle diameter measured by the TEM observation method of the inorganic fine particles is in the range of 1 to 200 nm,
The pore volume (PV _N ) measured by the nitrogen adsorption method is in the range of 0.1 to 2.0 cc / g, the average pore diameter is in the range of 5 to 60 nm, and the ink receiving layer measured by the mercury intrusion method is used. A recording sheet with an ink-receiving layer having a pore volume (PV _Hg ) in the range of 0.01 to 1.4 cc / g and an average pore diameter in the range of 5 to 40 nm.

[12] The water absorption amount (PV _H2O ) of the ink receiving layer is in the range of 0.1 to 2.0 cc / g, and the water absorption amount (PV _H2O ) and the pore volume (PV _Hg ) the ratio _{(PV H2O) / (PV Hg} ) recording sheets with an ink-receiving layer [11] in the range of 1.4 to 100.

[13] The inorganic fine particles are MgO, TiO ₂ , SiO ₂ , ZrO ₂ , Al ₂ O ₃ , Sb ₂ O ₅ , Z
The ink according to [11] or [12], which is at least one selected from the group consisting of nO and these complex oxides and having an average particle diameter measured by a dynamic light scattering method in the range of 5 to 10,000 nm. Recording sheet with receptor layer.

  [14] The recording sheet with an ink receiving layer according to [11] to [13], wherein the inorganic fine particles are pseudo boehmite alumina and / or boehmite alumina.

  [15] The recording sheet with an ink receiving layer according to [11] to [14], wherein the inorganic fine particles have a chain structure.

  [16] For recording with an ink receiving layer according to [11] to [15], wherein the core portion of the swellable resin particles is made of one or more resins selected from acrylic resin fine particles, urethane resin fine particles, and vinyl resin fine particles. Sheet.

[17] The ink receiving layer according to [11] to [16], wherein the ink receiving layer is obtained by applying the coating liquids of [1] to [10] on a base sheet, followed by drying and heating. Recording sheet with ink receiving layer.

[18] The swellable resin constituting the cell layer of the swellable resin particle includes a polymer main chain derived from a (meth) acrylic resin, and has a carboxyl group, a carbonyl group, a hydroxyl group, an amino group at the side chain or the terminal. Including one or more functional groups selected from the group consisting of a group, a halogen group, a urethane group, an alkyl group, a phenyl group, a sulfone group, an alkoxyl group, a thiol group, and a cyano group,
A resin matrix (i) a polymer component derived from polymerizable unsaturated monomers; and (ii)
(Iii) A recording sheet with an ink-receiving layer according to [11] to [17], comprising a polymer resin and (iii) crosslinked together with a swelling resin of a cell layer by a crosslinking agent.

According to the present invention, swellable resin fine particles, polymerizable unsaturated monomers, and polymer resins having a core cell structure comprising a resin core part and a cell part having an organic chain having a functional group bonded to the surface of the core part are cross-linked with each other. Since the ink receiving layer has a swellability, when the ink is applied, the receiving layer swells and the dye can penetrate into the ink receiving layer and be fixed, and the pigment can be fixed in the ink receiving layer. It can be fixed on the surface, and the swelling disappears and shrinks as the dispersion medium evaporates, so it has excellent ink absorption, dye fixing properties, scratch resistance, etc., and at the same time, excellent transparency, gas barrier properties, It is possible to provide a recording sheet with an ink-receiving layer and a coating liquid for forming an ink-receiving layer, which are capable of high-speed recording, high definition, full color, and excellent in image clarity. In particular, in the present invention, since inorganic fine particles having a predetermined average pore diameter and pore volume are contained, the fixability of the pigment / dye is high and the water resistance of the printed matter can be improved.

Hereinafter, the present invention will be specifically described.
[Ink-receiving layer forming coating solution]
The ink receiving layer forming coating solution according to the present invention is:
Swellable resin particles having a core cell structure having a cell layer made of a swellable resin,
Polymerizable unsaturated monomers,
Polymer resin,
It consists of a crosslinking agent, inorganic fine particles and a dispersion medium.

Swellable resin particles The swellable resin particles used in the present invention have a cell layer made of a swellable organic resin. Such swellable resin particles crosslink with a resin matrix component described later to form a network structure in the ink receiving layer.

  The average particle diameter of the swellable resin particles is in the range of 15 to 500 nm, preferably 20 to 400 nm. If it exists in this range, when bridge | crosslinking with a resin matrix and forming a network structure, the network structure which has a desired void | hole can be formed.

  In addition, if the swellable resin particles are small, the thickness of the cell layer is thin and sufficient swellability cannot be obtained, and the absorption and penetration of the dye is suppressed due to the small size of the network structure. There is.

  If the swellable resin particles are too large, it varies depending on the type of polymer resin to be cross-linked, the type of polymerizable unsaturated monomers, the quantity ratio, etc., but the size of the network is too large and changes due to swelling and shrinkage are large. In some cases, the ink receiving layer may crack or haze.

In the present invention, the average particle diameter of the swellable resin particles can be measured by a dynamic light scattering method. In the dynamic light scattering method, a sample is prepared mainly in an excess of an aqueous dispersion medium (which may contain alcohol). For this reason, the swellable resin particles are swollen, and the average particle diameter is measured for the swollen particles.
Core particles In the swellable resin particles used in the present invention, the core is also composed of a resin.

  As the core, a conventionally known resin can be used. Examples thereof include (meth) acrylic resins, urethane resins, vinyl resins, polyester resins, polyamide resins, polyphenylene oxide resins, fluorine resins, silicone resins, sulfone resins, and cellulose derivatives. These resins can be used alone or in combination of two or more.

  Further, as the (meth) acrylic resin, for example, (meth) acrylic acid ester such as methyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer , Methyl methacrylate-acrylic acid ester- (meth) acrylic acid copolymer, (meth) acrylic acid ester-styrene copolymer (MS resin and the like), and the like.

  These resins preferably have a functional group, specifically, carboxyl group, carbonyl group, hydroxyl group, amino group, halogen group, urethane group, alkyl group, phenyl group, sulfone group, alkoxyl group, vinyl group. And functional groups of derivatives thereof. By having these functional groups, hydrophobicity and solubility parameters can be adjusted, and desired core fine particles can be prepared. In addition, these functional groups can be used individually or in combination of 2 or more types.

  In the present invention, acrylic resin fine particles, urethane resin fine particles, and vinyl resin fine particles are suitably used as the core. These core particles are easy to prepare desired swellable resin particles having a core cell structure, and the refractive index is close to alumina fine particles, silica fine particles and the like commonly used as inorganic fine particles described later, For this reason, light scattering is suppressed, and an ink receiving layer excellent in transparency, haze, and the like can be obtained.

The average particle diameter of the resin fine particles constituting the core is preferably in the range of 10 to 150 nm, more preferably 15 to 100 nm. Within this particle size range, it is easy to prepare the swellable resin particles, and the resulting swellable resin particles are uniformly dispersed in the ink-receiving layer-forming coating material so that the desired dye-fixing property is obtained in the ink-receiving layer. It is effective for forming an effective network structure.
Cell layer The cell layer is made of a swellable organic resin bonded (grafted) to the surface of the core resin fine particles. In the cell layer, the swellable resin exists in the dispersion medium in a stretched state like soot, and shrinks when dried.

  The swellable organic resin constituting the cell layer preferably has a main chain made of a (meth) acrylic resin. For example, a (meth) acrylic acid ester such as methacrylic acid or methyl methacrylate, methyl methacrylate- (meta ) Acrylic acid copolymer, Methyl methacrylate- (meth) acrylic acid ester copolymer, (Meth) methyl acrylate-Acrylic acid ester- (Meth) acrylic acid copolymer, (Meth) acrylic acid methyl-acrylic acid Examples thereof include an ester- (meth) acrylic acid copolymer and a (meth) acrylic acid methyl-urethane copolymer.

  The swellable organic resin constituting the cell layer preferably has a functional group, specifically, a carboxyl group, a carbonyl group, a hydroxyl group, an amino group, a halogen group, a urethane group, an alkyl group, a phenyl group, a sulfone group. , One or more functional groups selected from the group consisting of an alkoxyl group, a thiol group, and a cyano group, and derivatives thereof. By introducing such a functional group, it is possible to adjust the hydrophobicity and solubility parameters and form a cell layer suitable for the core portion described above. In addition, a carboxyl group, a carbonyl group, or the like having a double bond can increase the degree of crosslinking after formation of the receiving layer. These functional groups can be used alone or in combination of two or more.

  Such a functional group may be bonded to the main chain as a side chain or may be bonded to the terminal.

Specifically, as the lubricating organic resin, a polymer of a component having a polymerizable double bond that becomes the main chain of the lubricating organic resin and a compound in which the functional group or a group having a functional group is bonded to a side chain Is used. The monomer or polymer constituting the main chain of the lubricating organic resin and the compound having the functional group may be a copolymer or polycondensate.

When the lubricating organic resin is a polymer of a single monomer, the functional group may have one or more functional group compounds together with one or more double bonds in one monomer. Further, when each of the main chain and side chain compounds is used, the component derived from the compound constituting the side chain is 100 to 1000 mol% with respect to 1 mol of the structural unit derived from the main chain compound. Preferably, it is contained in the range of 100 to 400 mol%.

  Examples of the compound having a functional group include hydroxyethyl (meth) acrylate and N-dimethylaminoethyl acrylate.

  With such a functional group amount, it is easy to form a crosslink with a resin matrix forming component described later. Moreover, the swelling property of the swelling resin is increased.

  The swellable organic resin constituting such a cell layer preferably has a weight average molecular weight in the range of about 5000 to 20000.

  In the coating solution, the swellable resin particles are swelled and dispersed in the cell layer. In the ink receiving layer, the resin matrix is cross-linked with each other to form a network structure. Further, at the time of in-coating, the ink is swelled by the ink dispersion medium and is no longer swellable due to the evaporation of the dispersion medium and contracts.

  The thickness of the cell layer is preferably 2.5 to 150 nm, more preferably 5 to 100 nm.

  When the thickness of the cell layer is in the above range, it is possible to form a tough and flexible ink receiving layer structure free from ink absorption, cracking due to drying, and haze generation.

  When the thickness of the cell layer is small, sufficient swelling cannot be obtained, and in addition, since the mesh size of the network structure is small, dye absorption and penetration may be suppressed. When the thickness of the cell layer is thick, the mesh size of the network structure becomes too large, and the change due to swelling and shrinkage is large, so that the ink receiving layer may be cracked or haze may occur.

  In the present invention, the average particle diameter of the core particles can be measured by a dynamic light scattering method, and the cell layer is calculated from the whole particle obtained by subtracting the core particle content.

In the coating liquid for forming an ink receiving layer, the swellable resin particles are swollen by inserting a dispersion medium and a solvent between the main chains of the swellable resin constituting the cell layer. In the ink receiving layer, it is dried and shrinks as the solvent disappears. Therefore, when ink is applied, the ink receiving layer swells and the dye can penetrate into the ink receiving layer and be fixed. The pigment is fixed on the surface of the ink receiving layer (some may reach the cell layer). It is considered that as the dispersion medium evaporates, the swelling state is eliminated and contracts, and as a result, the ink absorbed in the ink receiving layer is strongly pressed into the ink receiving layer with the contracted network structure.
Method for Producing Swellable Resin Particles The method for producing swellable resin particles having such a core cell structure can be produced according to the method described in TECHNO-COSMOS 2005 Mar. VoL.18.

For example,
(1) Polymer emulsifier method:
A pre-emulsion solution of acrylic monomer is prepared using a water-soluble polymer resin (emulsifier). This water-soluble polymer resin corresponds to the cell layer. By dropping it into an aqueous medium together with a polymerization initiator and polymerizing the acrylic monomer, swellable resin particles (emulsion resin) consisting of a water-soluble polymer resin whose core is an acrylic polymer and whose cell layer is an emulsifier are obtained. It is done.
(2) Two-stage emulsion polymerization method:
First, a hydrophilic emulsion resin containing a water-soluble carboxylic acid to be a cell layer is synthesized. The hydrophilic emulsion resin containing carboxylic acid is obtained by condensation polymerization of 2-hydroxyethyl succinic acid, methacrylic acid or the like.

  Specifically, the acrylic monomer pre-emulsion solution prepared using an anionic reactive emulsifier such as dodecylbenzene sulfonic acid is dropped into an aqueous medium together with a polymerization initiator to cause a polymerization reaction. A hydrophilic emulsion resin containing an acid is obtained. The number average molecular weight of the emulsion resin at this time is approximately 5000 to 20000.

  Next, using the obtained hydrophilic emulsion resin containing a carboxylic acid as a polymerization field, the acrylic monomer mixture is dropped as monomer oil droplets without using an emulsifier to obtain a core cell type emulsion resin in which the hydrophobic core portion is polymerized. .

  The obtained core polymer is made into a core particle, and the core cell particle having a hydrophilic emulsion resin containing carboxylic acid as a cell is neutralized with an amine to make the cell layer water-soluble, thereby making the hydrophobic core part water-soluble. Swellable resin particles encapsulated in the resin (cell layer) are obtained.

  In the above method, an emulsion corresponding to the cell layer is prepared, and then a monomer mixture constituting a core particle and a pH adjuster are added, and a polymerization reaction is performed here to prepare a core. Thereby, swellable particles having a core cell structure are obtained.

The core particle is formed by the growth of a monomer mixture for forming a copolymer constituting the core, and the growth is controlled by the addition of a pH adjusting agent.
(3) Alternative method First, spherical core particles are obtained by stirring an acrylic resin forming a core, such as pentaerythritol tetraacrylate, and alcohol at high speed. Next, swellable fine particles having a core cell structure are obtained by adding highly hydrophilic, for example, hydroxyl group-containing 2-hydroxyethyl acrylate, a polymerization initiator for cell layer preparation and an acrylic surfactant, adjusting the pH to near neutral and stirring. be able to.

Regarding the mechanism by which the swellable resin particles having such a core cell structure exhibit swelling properties, for example, in an aqueous dispersion of core cell particles in which an organic chain having a carboxyl group as a functional group is bonded, the carboxyl group of the cell is ionized and carboxyl It is believed that electrostatic repulsion between ions swells by overcoming the hydrophobic bond between the hydrophobic group of the cell and the hydrophobic group present on the cell or core surface. (Reference: Toyota Central R & D Review VoL.30.NO.2 (1995.6)
The same can be inferred for other hydrophilic groups as well.

The polymerizable unsaturated monomer coating solution contains polymerizable unsaturated monomers.

(i) The polymerizable unsaturated monomer is not particularly limited as long as it can crosslink with the swellable resin particles and the polymer resin described later, and a conventionally known monomer having a binding double bond can be used.

Specifically, (meth) acrylic resins, organic acid vinyl ester resins, vinyl ether resins, halogen-containing resins, ester resins, amide resins, urethane resins, cellulose derivatives (cellulose esters, cellulose carbamates, cellulose And ethers). These polymerizable unsaturated monomers can be used alone or in combination of two or more.

  As the (meth) acrylic resin, a (meth) acrylic monomer alone or a copolymer, a copolymer of a (meth) acrylic monomer and a copolymerizable monomer, or the like can be used. Examples of (meth) acrylic monomers include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, t-butyl (meth) acrylate, ( (Meth) acrylic acid such as isobutyl acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, alkyl (meth) acrylate such as 2-ethylhexyl (meth) acrylate, and phenyl (meth) acrylate Aryl, hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, N, N-dialkylaminoalkyl (meth) acrylate; (meth) acrylonitrile N, N- Dimethylaminoethyl acrylate, N, N-di Tilaminoethyl methacrylate, N, N-diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, N, N-dimethylvinylbenzylamine, etc. Can be illustrated. Examples of the copolymerizable monomer include the styrene monomer, vinyl ester monomer, maleic anhydride, maleic acid, and fumaric acid. These monomers can be used alone or in combination of two or more.

  Organic acid vinyl ester resins include vinyl ester monomers alone or copolymers (polyvinyl acetate, polyvinyl propionate, etc.), and vinyl ester monomers and copolymerizable monomers. Examples thereof include a copolymer (ethylene-vinyl acetate copolymer, vinyl acetate-vinyl chloride copolymer, vinyl acetate- (meth) acrylic ester copolymer, etc.) or a derivative thereof. Examples of the vinyl ester resin derivative include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl acetal resin, and the like.

  Examples of vinyl ether resins include vinyl alkyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, and vinyl t-butyl ether, or copolymers of vinyl alkyl ether and copolymerizable monomers ( Vinyl alkyl ether-maleic anhydride copolymer).

  Examples of the halogen-containing resin include vinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride- (meth) acrylic acid ester copolymer, and the like.

  These resins can have a functional group in addition to the unsaturated double bond, specifically, carboxyl group, carbonyl group, hydroxyl group, amino group, halogen group, urethane group, alkyl group, phenyl group. Group, sulfone group, alkoxyl group, vinyl group, thiol group and the like. In particular, a carboxyl group, a carbonyl group, and the like are preferable because they can increase the degree of crosslinking after formation of the receiving layer. These functional groups may be used alone or in combination of two or more.

  Such polymerizable unsaturated monomers constitute a network structure together with the swellable resin particles and the polymer resin when the ink receiving layer is formed. The polymerizable unsaturated monomers have high reactivity, are involved in the formation of a network structure, and can increase the crosslinking density. Therefore, it exhibits a function of increasing the retention of inorganic fine particles and swellable fine particles in the receiving layer.

Polymer resin In the present invention, the coating solution further contains a polymer resin.

  This polymer resin and the polymerizable unsaturated monomer constitute a resin matrix in the ink receiving layer.

  The polymer resin is not particularly limited as long as it can crosslink with the swellable resin particles and the resin monomer, and conventionally known ones can be used.

  The resin polymer used in the present invention is granular (polymer resin), and the average particle diameter is preferably in the range of 1 to 100 nm, more preferably 10 to 10 nm. Such a polymer resin is involved in the formation of pores in the network structure when crosslinked, thereby making it possible to improve the absorbability and fixability of dye inks and pigment inks.

  Examples of polymer resins include polymers such as acrylic resin fine particles, urethane resin fine particles, polyvinyl alcohol resin fine particles, vinyl resin fine particles, ethylene resin fine particles, polystyrene resin fine particles, ester resin fine particles, and epoxy resin fine particles. Can be mentioned.

  Among them, acrylic resin fine particles are excellent in crosslinkability with swellable resin particles and resin monomers, and are excellent in the formation of a network structure. Also, the refractive index is close to those of alumina fine particles, silica fine particles and the like that are commonly used as inorganic fine particles. In addition, when these inorganic fine particles are contained, light scattering is suppressed, and an ink receiving layer excellent in transparency, haze, and the like can be obtained.

The polymer resin is a component of the network structure in the ink receiving layer, and also has a function of mitigating residual stress generated when the swellable resin particles swell and contract and the adhesion between the substrate and the receiving layer. It has a function.

  If the average particle size of the polymer resin is too small, the ink-receiving layer itself is densified and the formation of pores is small, depending on the content of the swellable resin particles and inorganic fine particles. In some cases, the effect of use cannot be obtained, and ink absorbability, dye fixability, and the like are insufficient. If the average particle size of the polymer resin is too large, the crosslinkability (bondability with other components) is lowered, and an ink receiving layer having a desired network structure may not be obtained.

Crosslinking agent In this invention, a crosslinking agent is contained in a coating liquid. In the ink receiving layer, the crosslinking agent crosslinks the swellable resin particles, (i) a polymer of polymerizable unsaturated monomers, and (ii) the polymer resin,
Configure a mesh structure. In addition, inorganic fine particles may also be involved in this crosslinking. When the inorganic fine particles are also cross-linked, the strength of the ink receiving layer may be improved.

  There is no restriction | limiting in particular as a crosslinking agent, A conventionally well-known crosslinking agent can be used.

  Specifically, carbodiimide compounds (compounds having a carbodiimide group), polycarbodiimide compounds: several thousand molecular weights, cyan compounds, melamine compounds, oxazoline compounds (compounds having an oxazoline group), isocyanate compounds (-N = C = O partially It is preferably at least one selected from compounds having a structure.

Examples of the carbodiimide compound include carbodilite V-01 and V-02 (manufactured by Nisshinbo Co., Ltd.), and examples of the oxazoline compound include Epocross (manufactured by Nippon Shokubai Co., Ltd.).

Inorganic fine particles The ink receiving layer of the present invention contains inorganic fine particles.

  As the inorganic fine particles, conventionally known inorganic fine particles, preferably metal oxide fine particles and metal hydroxide fine particles can be used.

Specifically, MgO, TiO ₂ , SiO ₂ , ZrO ₂ , Al ₂ O ₃ , Sb ₂ O ₅ , ZnO, and hydroxides thereof (including hydrates) or composite oxide fine particles thereof are used. Can be mentioned.

  The inorganic fine particles used in the present invention may be monodispersed particles (hereinafter sometimes referred to as primary particles) or secondary particles in which the primary particles form an aggregate. The shape of the inorganic fine particles is not particularly limited, such as a spherical shape, a granular shape, a fibrous shape, a chain shape in which primary particles or secondary particles are linked in a chain shape, and the fibrous particles form a receptor layer as described later. In addition, since it is easy to form a three-dimensional space, the ink absorbability is easily improved, and therefore it can be suitably used.

  The average primary particle diameter of the inorganic fine particles can be obtained by observing a TEM photograph.

  Specifically, a transmission electron micrograph (TEM) of inorganic fine particles is taken, the particle diameter is measured for 100 particles, and the average value is obtained.

  The average particle diameter is preferably in the range of 1 to 200 nm, more preferably 2 to 100 nm.

  If the average particle diameter is smaller than this range, even if it is difficult to obtain, it may be amorphous with low crystallinity, and the dye fixability may be insufficient.

  If the average particle size is too large, the dispersibility may be lowered in a solvent, the stability of the receiving layer coating solution may be lowered, and even when the receiving layer is formed, the haze due to scattering is increased and a transparent substrate is formed. When used as a material, it may cause a decrease in transmittance, an increase in haze of the receiving layer, and a decrease in ink coloring property.

  When the inorganic fine particles are secondary particles, the average secondary particle diameter is measured by a dynamic light scattering method.

  The average secondary particle diameter is preferably in the range of 5 to 10,000 nm, more preferably 10 to 5,000 nm.

  It is difficult to obtain secondary particles in which the average secondary particle size of the inorganic fine particles is smaller than the lower limit of the above range, and even if obtained, it may be amorphous with low crystallinity. Since the pores cannot be formed sufficiently, the ink absorbability may be insufficient.

  If the average secondary particle size of the inorganic fine particles is too large, the dispersibility may be lowered in a solvent, the stability of the receiving layer coating solution is also lowered, and the pore volume is large even when the receiving layer is formed. However, the balance between the vertical penetration speed and the horizontal penetration speed is lost, ink bleeding occurs, the ink color develops poorly, and the transmittance decreases and is accepted when used on a transparent substrate. May cause an increase in layer haze.

Next, the fine inorganic particles used in the present invention have a pore volume (PV _N ) of 0.1 measured by the nitrogen adsorption method.
It is preferable to be in the range of -2.0 cc / g, more preferably 0.2-1.5 cc / g.

If the pore volume (PV _N ) of the inorganic fine particles is small, the pore volume when the receiving layer is formed is too small, the ink absorption rate is slow, bleeding may occur, and ink fixing may be insufficient. is there.

Even if the pore volume (PV _N ) of the inorganic fine particles is too large, the ratio of the pore volume due to the interparticle pores of the secondary particles becomes large, and when the receptor layer is formed, the average pore diameter is too large and the ink The ink may not be sufficiently fixed, the ink may have insufficient fixability, and the gap between the matrix component of the receiving layer and the particles may become too large, resulting in a decrease in strength or cracks.

The average fine pore diameter of the inorganic fine particles is preferably in the range of 5 to 60 nm, more preferably 5 to 40 nm. (There are no pores exceeding the particle size)
If the average pore size of the inorganic fine particles is too small, the pore size of the ink receiving layer is too small, resulting in insufficient ink adsorbability and dye fixing properties, causing ink repellency, and pigment fixing in the case of pigment inks. May be insufficient. If the average fine pore diameter of the inorganic fine particles is too large, the average fine pore diameter becomes too large in the receiving layer, which may cause ink bleeding, dye fixing property, and ink coloring property.

  In the present invention, among the inorganic fine particles, pseudo boehmite alumina fine particles and boehmite alumina fine particles can be suitably used.

  The pseudo boehmite alumina fine particles and boehmite alumina fine particles have a fibrous shape, the average width thereof is generally in the range of 1 to 20 nm, and the average length is in the range of 5 to 100 nm.

When such fibrous pseudo-boehmite alumina fine particles or fibrous boehmite alumina fine particles are used, since there are many —OH groups on the particle surface, high pore volume, and positive charge, the desired pore diameter and pore volume are reduced. As a result, it is possible to obtain an ink receiving layer having high ink absorptivity, high color developability, and high fixability of negatively charged dye / pigment ink.

If the average primary particle length (L ₁ ) is short, it is difficult to form a three-dimensional space, and when the ink receiving layer is formed, an ink receiving layer having a desired average pore diameter and pore volume range cannot be obtained. In some cases, ink repelling occurs, and the pigment ink has sufficient fixability. If the average length (L ₁ ) of the primary particles is too long, the average pore diameter and the average pore volume become too large when the receptor layer is formed, which may cause ink bleeding and a decrease in ink coloring property. .

It is difficult to make the average width (W ₁ ) of the primary particles smaller than the above range, and if the average width (W ₁ ) is too large, the effect of using the fibrous particles is hardly exhibited when the receiving layer is formed. Become.

  Inorganic fine particles and resins usually do not crosslink (bond), but in the case of inorganic fine particles treated with a resin having a specific functional group and a surface treatment agent that binds to the functional group, or radicals are generated in the inorganic fine particles. In some cases, such as when polymerized, it may be crosslinked (bonded).

Dispersion medium The dispersion medium used in the present invention is not particularly limited as long as it can disperse the swellable resin particles, resin matrix components (polymerizable unsaturated monomers and polymer resins), cross-linking agent, and inorganic fine particles. These solvents can be used.

Specifically, alcohols such as water, methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, hexylene glycol, isopropyl glycol; acetic acid Esters such as methyl ester, ethyl acetate, butyl acetate; ethers such as diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether Acetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetone Ketones such as acetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, toluene, cyclohexanone, isophorone and the like.

  These may be used alone or in combination of two or more. Moreover, you may add an antifoamer and a leveling agent as needed.

Coating liquid composition A coating liquid for forming an ink receiving layer according to the present invention comprises a swellable resin particle having a core cell structure, a polymerizable unsaturated monomer, a polymer resin, a crosslinking agent, inorganic fine particles, and a dispersion medium. The content concentration is in the range of 1 to 50% by weight, the concentration of the swellable resin particles is in the range of 0.05 to 40% by weight as the solid content, and the concentration of the polymerizable unsaturated monomers is 0.01 as the solid content. In the range of ~ 20 wt%, the concentration of the polymer resin is in the range of 0.01 to 10 wt% as the solid content, the concentration of the cross-linking agent is in the range of 0.001 to 10 wt% as the solid content, inorganic The concentration of the fine particles is in the range of 0.01 to 45% by weight as a solid content (provided that the total is 1
It does not exceed 00% by weight).

  The swellable resin particles having a core cell structure contract during normal drying but swell in the coating solution. In the coating solution, the functional groups of the swellable organic resin repel each other electrostatically in the cell layer, and the solvent swells between the organic main chains.

  The polymerizable unsaturated monomers and the polymer resin are usually not crosslinked in the coating solution, but may be partially crosslinked.

  The concentration of each of these components is adjusted in the coating solution so as to be contained in the ink receiving layer at the aforementioned ratio and to have a viscosity suitable for coating.

  The total solid concentration of the ink receiving layer forming coating solution is preferably in the range of 1 to 50% by weight, more preferably 2 to 38% by weight. If the total solid content concentration is too low, a predetermined film thickness may not be obtained by a single application. For this reason, it is necessary to repeat application and drying, which may be disadvantageous in terms of economy. Even if the total solid content concentration is too high, the thickness of the resulting receiving layer tends to be non-uniform.

  The concentration of the swellable resin particles in the ink-receiving layer-forming coating solution is used so that the content of the swellable resin particles in the resulting ink-receiving layer is in the above-described range. It is preferable to be in the range of ˜40% by weight, more preferably 0.1˜30% by weight.

  If there are few swellable resin particles in the ink-receiving layer-forming coating solution, the ink absorbability may be insufficient. Even if there are too many swellable resin particles, there are too many swellable resin particles in the resulting ink receiving layer, so that cracks may occur upon absorption and drying of the ink, and depending on the amount of other components May not be able to form a coating solution.

  The concentration of the polymerizable unsaturated monomer in the coating liquid for forming the ink receiving layer is used so that the content of the resin monomer in the obtained ink receiving layer is in the above-mentioned range. It is preferably in the range of ˜20% by weight, more preferably 0.02 to 15% by weight.

  When the amount of the polymerizable unsaturated monomers is small, the initiation of crosslinking is delayed and the number of crosslinking initiation points is small, the formation of the network structure is insufficient, and the effect of the present application due to the network structure may not be obtained. If there are too many polymerizable unsaturated monomers, the crosslinking between the monomers becomes the main, and the crosslinking between the swellable resin particles and the resin polymer to be described later becomes insufficient. The resulting effect of the present application may not be obtained.

  The concentration of the polymer resin in the coating liquid for forming the ink receiving layer is used so that the content of the polymer resin in the obtained ink receiving layer is within the above-described range, but is generally 0.01 to 10% by weight as a solid content. Furthermore, it is preferable to be in the range of 0.02 to 7.5% by weight.

  If the amount of the polymer resin is small, the crosslinkability is insufficient and an ink receiving layer having a desired network structure may not be obtained, and even if it is obtained, cracks may occur. Even if the amount of the polymer resin is too much, the content of the swellable resin particles and inorganic fine particles is decreased, and the ink receiving layer is densified, so that the ink absorption characteristics may be lowered.

  The concentration of the crosslinking agent varies depending on the type of the swellable resin particles, the particle diameter, the concentration, and the amount of the resin matrix components (polymerizable unsaturated monomers and polymer resin) used. %, More preferably in the range of 0.002 to 7.5% by weight.

  When the amount of the crosslinking agent is small, the cross-linking of the swellable resin particles and the resin matrix components (polymerizable unsaturated monomers and polymer resin) becomes insufficient, resulting in insufficient formation of a network structure and poor ink absorbability. In some cases, the ink receiving layer becomes cracked during ink absorption or drying. Even if the cross-linking agent is further increased, mutual cross-linking is not promoted, and the ink absorbability may be lowered.

  The concentration of the inorganic fine particles in the ink receiving layer forming coating solution is preferably in the range of 0.01 to 45% by weight, more preferably 0.02 to 34% by weight as the solid content. If the amount of inorganic fine particles is too small, the water-based ink may have insufficient absorption characteristics. Moreover, when there are too many inorganic fine particles, the haze of the ink receiving layer obtained may deteriorate.

The amount of the polymerizable unsaturated monomer is 10 to 200 parts by weight with respect to 100 parts by weight of the swellable resin particles.
Preferably it is in the range of 20 to 100 parts by weight.

  The polymer resin content is desirably 5 to 150 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of the swellable resin particles.

The polymer resin content is desirably in the range of 5 to 200 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of the polymerizable unsaturated monomers.
The crosslinking agent is desirably in the range of 1 to 100 parts by weight, preferably 2 to 80 parts by weight, based on 100 parts by weight of the polymerizable unsaturated monomers.

The amount of inorganic fine particles is 10 to 500 parts by weight, preferably 20 parts per 100 parts by weight of the swellable resin particles.
It is desirable to be in the range of ~ 400 parts by weight.
Such a coating solution for forming an ink receiving layer can be prepared by mixing the above-mentioned components by a known method.

The above-described coating solution for forming the ink receiving layer is formed by using the bar coating method, blade coating method, air knife method, roll coating method, brush coating method, gravure coating method, slit coating method, kiss coating method, extrusion method, slide hopper (slide bead). ) Method, curtain coat method, dam coat method, spray method, etc., the ink receiving layer can be formed by applying to a substrate, drying, and heat treatment as necessary.

  In the present invention, a bar coating method, a slit coating method, a gravure coating method, a curtain coating method, and a dam coating method are recommended.

  As a drying method, a conventionally known method can be adopted, and the drying is generally performed at 30 to 120 ° C. for 0.1 to 2 hours.

  In the present invention, at the time of drying, the resin is cross-linked and cured by the cross-linking agent used in the coating solution at the time of drying. If the curing is insufficient, then heat treatment may be performed. At the time of forming the ink receiving layer, not all are cross-linked, but some are cross-linked, and the cross-linking is further advanced in printing.

  The heat treatment is performed at a temperature higher than the drying temperature, generally at 50 to 150 ° C. for 0.1 to 2 hours.

  These may be used alone or in combination of two or more. Moreover, you may add an antifoamer and a leveling agent as needed.

  The above-described coating solution for forming the ink receiving layer is formed by using the bar coating method, blade coating method, air knife method, roll coating method, brush coating method, gravure coating method, slit coating method, kiss coating method, extrusion method, slide hopper (slide bead). ) Method, curtain coat method, dam coat method, spray method, etc., the ink receiving layer can be formed by applying to a substrate, drying, and heat treatment as necessary.

  In the present invention, a bar coating method, a slit coating method, a gravure coating method, a curtain coating method, and a dam coating method are recommended.

  As a drying method, a conventionally known method can be adopted, and the drying is generally performed at 30 to 120 ° C. for 0.1 to 2 hours.

  In the present invention, at the time of drying, the resin is cross-linked and cured by the cross-linking agent used in the coating solution along with the drying. If the curing is insufficient, then heat treatment is performed.

  The heat treatment is performed at a temperature higher than the drying temperature, generally at 50 to 150 ° C. for 0.1 to 2 hours.

  The ink receiving layer thus obtained has a network structure and has swelling properties, excellent ink absorbability, dye and pigment fixing properties, etc., light resistance, water resistance, kill resistance, An ink receiving layer having excellent gas barrier properties and the like can be obtained.

  In particular, since specific inorganic particles are contained, the ink absorption rate is high and the fixability of pigments and dyes is high. Therefore, no bleeding occurs, the strength is high, and no cracks occur in the ink receiving layer.

It has excellent ink absorption, dye / pigment fixability, scratch resistance, etc., and at the same time, excellent transparency, gas barrier properties, etc., enabling high-speed recording, high definition, full color, and image clarity. An excellent recording sheet with an ink receiving layer can be provided.
[Recording sheet with ink receiving layer]
The recording sheet with an ink receiving layer according to the present invention comprises a base sheet and an ink receiving layer formed on the base sheet.
As the base sheet used in the present invention, a conventionally known sheet can be used without particular limitation, and paper having an appropriate size, non-size paper, resin-coated paper, glass, polycarbonate, poly Vinyl chloride resin (PVC), acrylic resin, polyethylene terephthalate (PET), triacetyl cellulose (TAC), cyclopolyolefin, norbornene and other plastic sheets, plastic films, plastic panels, polyester fibers, silicon substrates, metals, etc. can give. Among these, paper and resin base materials can be preferably used. Moreover, the base material with a film in which another film was formed on such a base material can also be used. Examples of other coatings include conventionally known primer films, hard coat films, and mat layer films.
Ink-receiving layer The ink-receiving layer comprises swellable resin particles having a core cell structure as described above, a resin matrix, and inorganic fine particles.

  The ink receiving layer is composed of a resin matrix composed of a polysaturated unsaturated monomer and a polymer resin, swellable fine particles, and inorganic fine particles. The pores of the receiving layer are mainly due to the presence of inorganic fine particles and swellable fine particles, and the matrix component and the cell layer of the swellable resin are cross-linked by a cross-linking agent.

  In the swellable particles, the core surface and the cell are crosslinked, and the cell interior is also crosslinked. Among the structures, the conventional receiving layer has utilized the pores in the gap between the matrix component and the fine particles to absorb and fix the ink. However, the present invention introduces the ink by introducing the swellable fine particles. When the swellable resin swells due to the influence of water during implantation, the pores obtained by swelling are added to the pores between the matrix component and the inorganic fine particles, and the conventional receiving layer has a large pore volume (there are many inorganic fine particles) Ink absorbency (speed) as expressed in the The dye penetrates and is fixed in the swellable fine particles, and a part of the pigment is fixed in the cell layer of the swellable fine particles. Therefore, the fixing property is higher than that of the conventional receiving layer fixed in the gap between the matrix component and the fine particles.

  Inorganic fine particles and resin usually do not crosslink (bond), but in the case of inorganic fine particles treated with a resin having a specific functional group and a surface treatment agent that binds to the functional group, or by generating radicals in the inorganic fine particles, polymerization In some cases, it may be crosslinked (bonded). By including such inorganic fine particles, ink absorbability, dye fixability, and scratch resistance can be improved.

1 to 100 nm ² the size of the mesh of the mesh structure formed, it is estimated that preferably is in the range of 2 to 80 nm ^2. The measurement of the network structure is an estimated value from the size of inorganic fine particles, core cell particles, and the like.

  The resin matrix forms a network structure with the swellable resin particles in the ink receiving layer.

The resin matrix is composed of (i) a component derived from polymerizable unsaturated monomers, and (ii) a polymer resin. (i) The polymerizable unsaturated monomers are polymers in the ink receiving layer.

  The network structure does not necessarily have a grid shape, and may be any size and shape that allows a desired dye to enter the ink receiving layer.

In addition, since the ink receiving layer of the present invention is configured to include resin particles having swelling properties, the size of the mesh expands due to ink absorption during printing (referred to as an open leg). And the dye is absorbed inside the receiving layer. At this time, the transparency may be temporarily lost (haze may occur).

  Next, it is closed with drying, and the permeated dye is surrounded and protected by the resin. For this reason, it is considered that the dye does not change color and high gas barrier properties can be obtained. Further, since cross-linking also proceeds due to excessive heating during drying, the ink is further firmly fixed.

  In addition, it is considered that the pigment is in the form in which the ink swelling type core cell resin fine particles remain on the surface and, like the dye, part of the pigment is incorporated into the network structure and fixed at the time of printing. As a result, since the pigment is firmly fixed to the receiving layer as compared with a normal ink receiving layer, the scratch strength and the like are increased.

  Components other than ink dyes and pigments (ink water) such as hydrophilic solvents and surfactants are also received in the ink receiving layer. In general, it is considered that the print quality cannot be maintained unless ink water is received in addition to dyes and pigments. In the case of dye ink, ink water also penetrates into the receiving layer together with the dye. In the case of a pigment ink, the ink water penetrates into the receiving layer, and the swellable resin particles remain on the surface of the pigment. According to the present invention, the ink receiving layer has high ink water and high absorptivity, and therefore has excellent print quality without aggregation of the pigment to be fixed or deterioration of flatness.

Constitution of the ink receiving layer The content of the swellable resin particles in the ink receiving layer is preferably in the range of 5 to 80% by weight, more preferably 10 to 60% by weight as the solid content. Within this range, the ink absorbency is high. If the content of the swellable resin particles in the ink receiving layer is small, pores having a volume sufficient to absorb the ink cannot be formed, causing bleeding, or swelling after absorbing the ink and then shrinking by drying. However, gas barrier properties may be insufficient due to insufficient shrinkage. If the content of the swellable resin particles in the ink receiving layer is too high, the entire ink receiving layer swells, the cross-linking between the components is cut, and cracks may occur when dried.

  The content of the inorganic fine particles in the ink receiving layer is preferably in the range of 20 to 90% by weight, more preferably 30 to 85% by weight as the solid content.

  If there are few inorganic fine particles in an ink receiving layer, the hydrophobicity of an ink receiving layer will become strong and the absorption characteristic of water-based ink may become inadequate. Even if there are too many inorganic fine particles in an ink receiving layer, the haze of an ink receiving layer may fall.

Further, the pore volume (PV _Hg ) of the ink receiving layer measured by the mercury intrusion method of the ink receiving layer is in the range of 0.01 to 1.4 cc / g, more preferably 0.05 to 1.35 cc / g. The average pore diameter is preferably 5 to 40 nm, more preferably 10 to 35 nm.

If the pore volume (PV _Hg ) of the ink receiving layer is too small, the ink absorption depends on the swellable resin particles, and a sufficient ink absorption rate cannot be obtained. May occur. If the pore volume (PV _Hg ) of the ink receiving layer is too large, the pore volume is too large and ink bleeding occurs, or the gap between the matrix component of the ink receiving layer and the inorganic fine particles becomes too large, and the strength is high. It may decrease or cracks may occur.

If the average pore diameter of the ink receiving layer is too small, a sufficient ink absorption rate cannot be obtained, and ink bleeding and repellency may be likely to occur. If the average pore size of the ink receiving layer is too large, ink bleeding may occur, the dye fixing property may be insufficient, and the gap between the matrix component and the particles of the ink receiving layer may increase. May decrease or cracks may occur.

Further, the ink receiving layer of the present invention preferably has a water absorption amount (PV _H2O ) of 0.1 to 2.0 cc / g, more preferably 0.2 to 1.9 cc / g. If the amount of water absorption (PV _H2O ) is too small, swelling may be insufficient or the pore volume may be small, and sufficient ink absorption speed cannot be obtained, resulting in ink bleeding or repellency. There is.

Too much water absorption (PV _H2O ) indicates too much pore volume or excessive swelling, resulting in ink bleed, reduced ink receiving layer strength, cracks May occur.

The amount of water absorbed (PV _H2O ) is determined by cutting the substrate with the receiving layer into 10 mm square under conditions of room temperature 22-25 ° C and humidity 40-60%, and dropping water onto the receiving layer from the surface and cut surface. Measure the amount just before overflowing and calculate per unit gram as water absorption.

Also, the ratio (PV _H2O ) / (PV _Hg ) of the amount of water absorbed (PV _H2O ) to the pore volume (PV _Hg ) is in the range of 1.4 to 100, more preferably 1.5 to 80. Is preferred.

Even if the ratio (PV _H2O ) / (PV _Hg ) is too small, the swellability of the receiving layer is low, the effect of using the swellable resin particles of the present invention is insufficient, and sufficient ink absorbability cannot be obtained, Ink bleeding or repellency may occur.

If the ratio (PV _H2O ) / (PV _Hg ) is too large, the entire ink receiving layer swells, the cross-links between the components are cut, and cracks may occur when dried. Further, the ink absorbability is not further improved.

Although depending on the dispersion form of the inorganic fine particles, the (PV _H2O ) / (PV _Hg ) of the inorganic fine particles is approximately 1 to 1.5, and there is almost no water-proofing effect. Also, only swellable fine particles (PV _H2O ) /
Although (PV _Hg ) depends on the crosslink density, (PV _H2O ) = 0.1 to 10 cc / g, (PV _Hg ) = 0.01 to 0.1, and (PV _H2O ) / (PV _Hg ) = about 10 to 100. Since resin PV alone is too small (PV _Hg ) and there are almost no pores, when ink is applied, the ink injection speed is faster than the prevention of swelling resin fine particles, and the ink may ooze or overflow. In the presence of inorganic fine particles, the pore diameter and volume that can withstand the ink absorption speed can be provided in advance, so that the ink does not bleed even if the ink driving speed increases, and penetrates and fixes in the receiving layer. Therefore, it is compatible with high-speed printers, and there are pores formed by inorganic fine particles and pores obtained by the prevention of swellable resin fine particles. Compared to a receiving layer of a combination of alcohol and inorganic fine particles, the thickness can be reduced, and the amount of inorganic fine particles added can be reduced.

  When the content of the resin matrix in the ink receiving layer is in the above range, a desired crosslinked structure is formed. Further, when the content is small, the amount of the components constituting the cross-linking is also small, so that the network structure is not sufficiently formed, and the effect of the present application due to the network structure may not be obtained.

  Even if the content is too large, cross-linking between the resin matrix is the main, and the cross-linking with the swellable resin particles and the polymer resin is insufficient, resulting in insufficient formation of the network structure, and the effect of the present application due to the network structure. May not be obtained.

The content of the cross-linking component in the ink receiving layer varies depending on the content of the swellable resin particles, the components derived from the polymerizable unsaturated monomers, and the content of the polymer resin and the amount of their cross-linkable functional groups. It is preferably in the range of 0.1 to 20% by weight, more preferably 0.2 to 15% by weight.

When the content of the crosslinking component is within the above range, an ink receiving layer having a network structure and excellent in ink absorption characteristics, strength, haze and the like can be obtained.

The thickness of the ink receiving layer according to the present invention is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm.

  If the thickness of the ink receiving layer is thin, ink absorbability may be insufficient. In addition, when the thickness of the ink receiving layer exceeds 100 μm, it is difficult to obtain by one coating, and it is problematic in terms of economy to perform multiple coatings, and the ink receiving layer is cracked. Or curling (curving or warping).

  As a method for performing recording by applying ink to the recording sheet with the ink receiving layer, an ink jet recording method is preferable, and this recording method effectively separates the ink from the nozzle and applies the ink to the recording medium. Any method can be used as long as the method is obtained.

  Since the crosslinking temperature is lower than the temperature at the time of printing drying, the crosslinking proceeds more by heat treatment such as drying after printing, and the ink is firmly fixed.

  In particular, the ink receiving layer of the present invention is composed of a specific swellable component, and the ink water is absorbed quickly by swelling. Moreover, since the swellable resin particles are uniformly dispersed by the matrix component, the entire ink receiving layer swells uniformly, and water can be uniformly introduced into the entire ink receiving layer, particularly the deep layer portion. As a result, there is no bleeding or cracking in printing.

  Such a recording sheet with an ink-receiving layer according to the present invention can be produced by applying the ink-receiving layer-forming coating solution onto a substrate sheet, drying and curing. Specifically, the ink receiving layer forming paint is a bar coating method, blade coating method, air knife method, roll coating method, brush coating method, gravure coating method, kiss coating method, extrusion method, slide hopper (slide bead) method. The receptor layer can be formed by coating on a substrate sheet by a known method such as curtain coating or spraying, drying, and curing by a conventional method such as ultraviolet irradiation or heat treatment.

In the recording sheet with an ink receiving layer of the present invention, a glossy film may be further formed on the ink receiving layer.
[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
[Example 1]
Swellable resin particles (1) Preparation of dispersion As core particles, water-soluble acrylic polymer (A) having a carboxyl group at the end (manufactured by Nippon Polyurethane Industry Co., Ltd .: NIPPOLAN, WL-530, solid content concentration 40 (6.4% by weight, dispersion medium: water) was dispersed in 40 g of water, and after sufficient stirring, 1 g of ethanol was added to prepare a water-soluble acrylic polymer (A) solution having a solid content concentration of 17% by weight. did. At this time,
The average particle diameter of the core particles measured by a laser light scattering method (Beckman Coulter: Coulter Model N4) was 50 nm.

Next, 100 g of N-dimethylaminoethyl acrylate (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as an ionic conductive monomer (B) containing a carbonyl group was added to a water-soluble acrylic polymer (A) solution having a solid concentration of 17% by weight. And stirring for 20 minutes at 40 ° C., followed by crosslinking (while the inner alkoxysilyl group appears outside the particle, hydrolyzes under the influence of residual water, becomes reactive, and initiates dehydration condensation) 4 g of an acrylic surfactant (manufactured by NOF Corporation: SUNBRIGHT, PA series, solid content concentration 40% by weight, dispersion medium: water, pH 8.0), which is a polyethylene glycol (PEG) derivative, is added as an agent (C), Stir at 40 ° C. for 20 minutes. At this time, the pH of the mixed solution was 7.0.

  Subsequently, coarse particles and foreign matters were filtered and removed by a filter having a pore diameter of 1 μm, and finally a swellable resin particle (1) dispersion having a solid content concentration of 15.0% by weight was prepared by adjusting the concentration.

The weight average particle diameter of the obtained swellable resin particles (1) measured by the laser light scattering method (Coulter Model N4) is shown in the table.

Preparation of Alumina Hydrate Particle (1) A sodium hydroxide aqueous solution having a concentration of 5% by weight was added dropwise to 1000 g of a 3% by weight aluminum chloride aqueous solution to adjust the pH to 7. Then, it stirred at 25 degreeC for 1 hour, and obtained the alumina hydrate gel. The obtained gel was subjected to suction filtration with a 10 μm polypropylene filter, separated into solid and liquid, and washed with 2000 g of 60 ° C. hot water.

  The obtained washing gel had a concentration of 12% by weight as a solid content. Nitric acid having a concentration of 10% by weight was added to the washed gel to adjust the pH to 3.5, and then dried at 120 ° C. for 2 hours to obtain alumina hydrate particles (1).

The crystal structure of the obtained alumina hydrate particles (1) by X-ray diffraction and the average primary particle size, average secondary particle size, average pore size and pore volume measured under the following conditions are shown in the table.

A dispersion liquid having an average primary particle size of alumina hydrate particles (1) having a solid content concentration of 0.001% by weight was prepared, dropped on a grid of a transmission electron microscope and dried at room temperature, and then a transmission electron microscope (TEM). A photograph was taken, the particle size of 50 particles was randomly measured, and this average value was taken as the primary particle size. For the fibrous particles, the short diameter and long diameter were measured.

Measurement of average pore diameter and pore volume by nitrogen adsorption method After firing alumina hydrate particles (1) at 550 ° C for 1 hour, nitrogen adsorption pore distribution measuring device (BELSORB-mini, manufactured by Nippon Bell Co., Ltd.) is used. The integrated value of the relative pressure (P / Po) used was 0.38 to 0.990, the pore volume, and the peak pore diameter on the adsorption side was the average pore diameter.

Average secondary particle diameter The cumulant particle diameter measured using the dynamic light scattering method (Otsuka Electronics Co., Ltd .: PER-III) was defined as the average secondary particle diameter. The average secondary particle diameter of the obtained alumina hydrate (1) was 150 nm.

Preparation of coating liquid (1) for ink-receiving layer formation 10 g of the swellable resin particle (1) dispersion obtained above and alumina hydrate adjusted to a solid content concentration of 15% by weight as inorganic fine particles. Particle (1) 10 g of dispersion, 4 g of polymerizable unsaturated monomer 2-hydroxyethyl acrylate (manufactured by Shin Nippon Rika Co., Ltd .: Rekagit BT-W) containing carboxylic acid as polymerizable unsaturated monomers, as polymer resin 3 g of acrylic resin fine particles (manufactured by Toagosei Chemical Co., Ltd .: UC-3510), carbodiimide compound as a crosslinking agent (
Nisshinbo Co., Ltd. product: Carbodilite V-02) 0.2 g was sufficiently mixed to prepare an ink-receiving layer-forming coating solution (1). Table 1 shows the composition and the like of the obtained coating liquid (1) for forming an ink receiving layer.

Preparation of recording sheet with ink receiving layer (1) Coating liquid (1) for forming an ink receiving layer was prepared by using PET film (Toray Industries, Inc .: Lumirror T-100,
It is applied with a bar coater (# 60) to a thickness of 100 μm, a refractive index of 1.65, a base material transmittance of 88.0%, a haze of 1.0% and a reflectance of 5.1%, and dried at 60 ° C. for 20 minutes. Thus, a recording sheet (1) with an ink receiving layer was prepared. At this time, the thickness of the ink receiving layer was 10 μm.

  The total light transmittance and haze of the obtained recording sheet with ink-receiving layer (1) were measured, and the results are shown in Table 1.

  The total light transmittance and haze were measured with an integrating spectrometer (manufactured by JASCO Corporation: V560).

  In addition, adhesion, scratch resistance, water resistance, water absorption, pore characteristics by mercury intrusion method, ink absorbability and gas barrier properties were evaluated by the following methods and evaluation criteria, and the results are shown in Table 1.

Pore properties PV (Hg) (pore volume, average pore diameter)
The receiving layer of the recording sheet with ink receiving layer (1) is peeled off from the base material, 0.2 g is measured up to a maximum pressure of 33000 psi using a mercury intrusion pore distribution measuring device (Quantachrome: Poremaster). The pore volume and average pore diameter were obtained. The results are shown in Table 1.
Water absorption PV (H ₂ O)
When the receiving layer of the recording sheet with ink receiving layer (1) is cut to 10 mm square, when water is dropped on the receiving layer, the amount immediately before the water overflows from the surface and cut surface is measured and calculated per unit gram. It was set as the amount of water absorption.

The surface of the recording sheet (1) with an adhesive ink-receiving layer (1) is made of 11 parallel scratches with a knife at intervals of 1 mm in length and width to make 100 squares, and a cellophane tape is adhered to this, and then the cellophane tape Adhesiveness was evaluated by classifying the number of squares remaining without peeling of the film when the film was peeled into the following four stages. The results are shown in Table 1.

Number of remaining squares: ◎
Number of remaining squares 90-99: ○
Number of remaining squares: 85 to 89: Δ
Number of remaining squares: 84 or less: ×
Scratch resistance was evaluated by reciprocating steel wool # 0000 on a scratch-resistant ink-receiving layer 10 times with a load of 50 g / cm ² and counting the number of scratches on the surface and classifying it into the following four stages. The results are shown in Table 1.

Number of scratches: ◎
Number of wounds 1 to 10: ○
Number of wounds 10-100: △
More than 100 scratches: ×
Ink absorbability As for ink absorbability, ink permeability and ink color development were evaluated by the following methods and evaluation criteria. The results are shown in Table 1.
Using a dye printer P9000 made of ink penetrable Canon, black, which is a CMY tertiary color, is printed in a solid color with a printing density of 100%, and the surface roughness of the printed part with an ultra-deep microscope (VK-9500) manufactured by Keyence. (Ra) was measured. Similarly, the surface roughness (Ra ₀ ) of the portion where printing was not performed was measured, and the difference in surface roughness δRa (μm) = (Ra) − (Ra ₀ ) was determined and evaluated according to the following criteria. The results are shown in Table 1.
Evaluation criteria
δRa ≦ 0.15: ◎
0.15 <δRa <0.3: ○
0.3 ≦ δRa <1.0: Δ
δRa ≧ 1.0: ×
Using the ink coloring property Canon dye printers P9000, black consisting of CMY third color as the ink in a single color, the print density solid printing in 10% increments from 0% to 100%, manufactured by integral spectrometer (JASCO Corporation : V560), the degree of color development (brightness) measured in the Lab space is measured, and the print density (
The correlation coefficient (K) between 0-100%) and L (brightness%) was determined and evaluated according to the following criteria.
Evaluation criteria
K ≧ 0.8: ◎
0.5 <K <0.8: ○
0.2 <K <0.5: Δ
K ≦ 0.2: ×
Gas barrier property The album preservation property was evaluated as gas barrier property.

  First, using a Canon dye printer P9000, print the tertiary color on the recording sheet (1) with an ink receiving layer, and after drying, insert it into the vinyl bag of the album, and after 3 months at room temperature The degree of discoloration / fading was observed for the portion exposed from the vinyl-based wrapping bag, evaluated according to the following criteria, and the results are shown in the table.

Evaluation criteria No discoloration was observed: ◎
Slight discoloration was observed: ○
Obviously discoloration was observed: △
Significant discoloration was observed: ×
When the 3 cm square receiving layer of the recording sheet (1) with a water-resistant ink receiving layer was immersed in sufficient water for 30 minutes and then dried at room temperature for 24 hours, the presence or absence of traces of water was observed, and the following evaluations were made. The results were shown in Table 1.
Evaluation criteria No trace of water was found: ◎
Slight traces of water were observed: ○
Clear traces of water were found: △
The film peeled: ×
[Example 2]
Preparation of swellable resin particle (2) dispersion In Example 1, 70 g of N-dimethylaminoethyl acrylate (Mitsubishi Gas Chemical Co., Ltd.) was used as the ionic conductive monomer (B) containing a carbonyl group. Acrylic surfactant which is a polyethylene glycol (PEG) derivative as a crosslinking agent (C) (manufactured by NOF Corporation: SUNBRIGHT, PA series, solid content concentration 40% by weight, dispersion medium: water, pH 8.0) A swellable resin particle (2) dispersion having a solid content of 15.0% by weight was prepared in the same manner except that 2.8 g was added. The weight average particle diameter of the obtained swellable resin particles (2) is shown in the table.

Preparation of Ink Receptive Layer Forming Coating Liquid (2) Ink Receptive Layer Forming Application was the same as in Example 1 except that 10 g of the swellable resin particle (2) dispersion having a solid content concentration of 15.0% by weight was used. Liquid (2) was prepared.

Preparation of recording sheet with ink receptive layer (2) In Example 1, ink receptivity was the same except that the ink receptive layer forming coating liquid (2) was used instead of the ink receptive layer forming coating liquid (1). A layered recording sheet (2) was prepared. At this time, the thickness of the ink receiving layer was 8 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorptivity and gas barrier properties of the obtained recording sheet with an ink receiving layer (2) were evaluated. The results are shown in Table 1.
[Example 3]
Preparation of Swellable Resin Particles (3) Dispersion In Example 1, 130 g of N-dimethylaminoethyl acrylate (Mitsubishi Gas Chemical Co., Ltd.) was added as an ionic conductive monomer (B) containing a carbonyl group. Cross-linking agent (C)
Except that 5.2 g of an acrylic surfactant (manufactured by NOF Corporation: SUNBRIGHT, PA series, solid content concentration: 40% by weight, dispersion medium: water, pH 8.0) is added as a polyethylene glycol (PEG) derivative. A swellable resin particle (3) dispersion having a solid content concentration of 15.0% by weight was prepared. The weight average particle diameter of the obtained swellable resin particles (3) is shown in the table.

Preparation of ink-receiving layer-forming coating solution (3) In Example 1, ink-receiving layer-forming coating solution was used except that 10 g of the swellable resin particle (3) dispersion having a solid content concentration of 15.0% by weight was used. Liquid (3) was prepared.

Preparation of recording sheet with ink receptive layer (3) In Example 1, ink receptivity was the same except that ink receptive layer forming coating liquid (3) was used instead of ink receptive layer forming coating liquid (1). A layered recording sheet (3) was prepared. At this time, the thickness of the ink receiving layer was 13 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorptivity and gas barrier properties of the obtained recording sheet with an ink receiving layer (3) were evaluated. The results are shown in Table 1.
[Example 4]
Preparation of Ink Receptive Layer Forming Coating Liquid (4) Swellable Resin Particles (1) Dispersion with a Solid Concentration of 15.0% by Weight Prepared as in Example 1 Alumina hydrate particles (1) adjusted to 5.8 g and solid content concentration of 15% by weight as inorganic fine particles
24.0 g of dispersion, 0.5 g of polymerizable unsaturated monomer containing carboxylic acid as a polymerizable unsaturated monomer (manufactured by Shin Nippon Rika Co., Ltd .: Rekagit BT-W), acrylic resin fine particles (Tojo) as a polymer resin Synthetic Chemical Co., Ltd .: UC-3510 (0.1 g) and a carbodiimide compound (Nisshinbo Co., Ltd .: Carbodilite V-02) 0.1 g as a cross-linking agent were sufficiently mixed to form an ink receiving layer forming coating solution (1 ) Was prepared.

Preparation of recording sheet with ink-receiving layer (4) In Example 1, ink receiving layer was similarly prepared except that the ink-receiving layer-forming coating solution (4) was used instead of the ink-receiving layer-forming coating solution (1). A layered recording sheet (4) was prepared. At this time, the thickness of the ink receiving layer was 10 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorptivity and gas barrier properties of the obtained recording sheet with ink-receiving layer (4) were evaluated, and the results are shown in Table 1.
[Example 5]
Preparation of Ink Receptive Layer Forming Coating Liquid (5) Swellable Resin Particles (1) Dispersion with a Solid Concentration of 15.0% by Weight Prepared as in Example 1 50.0 g, 4.0 g of alumina hydrate particle (1) dispersion adjusted to a solid concentration of 15% by weight as inorganic fine particles, polymerizable unsaturated monomer containing carboxylic acid as polymerizable unsaturated monomer (new Nippon Rika Co., Ltd .: Rekagit BT-W (2.0 g), polymer resin acrylic resin fine particles (Toagosei Chemical Co., Ltd .: UC-3510) 1.0 g, carbodiimide compound (Nisshinbo Co., Ltd.) as a cross-linking agent 0.25 g of Carbodilite V-02) was mixed well to prepare a coating solution (1) for forming an ink receiving layer.

Preparation of recording sheet with ink-receiving layer (5) In Example 1, the same procedure as in Example 1 except that the ink-receiving layer-forming coating solution (5) was applied instead of the ink-receiving layer-forming coating solution (1). A layered recording sheet (5) was prepared. At this time, the thickness of the ink receiving layer was 10 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorptivity and gas barrier properties of the resulting recording sheet with ink-receiving layer (5) were evaluated. The results are shown in Table 1.
[Example 6]
Preparation of ink-receiving layer-forming coating liquid (6) Swellable resin particles (1) dispersion having a solid content concentration of 15.0% by weight, prepared in the same manner as in Example 1. 5.8 g and silica fine particles (manufactured by JGC Catalysts & Chemicals Co., Ltd .: S-30L, solid content concentration 30% by weight, average primary average particle size 20 nm, average secondary particle size 120 nm, water dispersion medium) as inorganic fine particles 10. 0 g, 2.5 g of a polymerizable unsaturated monomer containing carboxylic acid as a polymerizable unsaturated monomer (manufactured by Shin Nippon Rika Co., Ltd .: Rikajit BT-W), acrylic resin fine particles (Toagosei Chemical Co., Ltd.) as a polymer resin ): UC-3510) 2.0 g, and a carbodiimide compound (Nisshinbo Co., Ltd .: Carbodilite V-02) 0.2 g as a crosslinking agent was sufficiently mixed to prepare a coating liquid (1) for forming an ink receiving layer. .

Preparation of recording sheet with ink receptive layer (6) Coating liquid (8) for forming an ink receptive layer was prepared from PET film (Toray Industries, Inc .: Lumirror T-100,
It is applied with a bar coater (# 60) to a thickness of 100 μm, a refractive index of 1.65, a base material transmittance of 88.0%, a haze of 1.0% and a reflectance of 5.1%, and dried at 40 ° C. for 10 minutes. Subsequently, the recording sheet (6) with an ink receiving layer was prepared by heat treatment at 60 ° C. for 30 minutes. At this time, the thickness of the ink receiving layer was 10 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorptivity and gas barrier properties of the obtained recording sheet with an ink receiving layer (6) were evaluated. The results are shown in Table 1.
[Example 7]
Preparation of coating liquid for forming ink receiving layer (7) 10 g of swellable resin particle (1) dispersion prepared in the same manner as in Example 1, and alumina hydrate particles adjusted to a solid content concentration of 15% by weight as inorganic fine particles (1) 10 g of dispersion, 4 g of polymerizable unsaturated monomer containing carboxylic acid as polymerizable unsaturated monomers (manufactured by Shin Nippon Rika Co., Ltd .: Rekagit, BT-W), acrylic resin fine particles (Tojo) as polymer resin Synthetic Chemical Co., Ltd. product: UC-3510) 3 g, cross-linking agent oxazoline compound (Nippon Shokubai Co., Ltd. product: Epocross)
A coating liquid (7) for forming an ink receiving layer was prepared by sufficiently mixing 0.3 g.

Preparation of recording sheet with ink receiving layer (7) Coating liquid (7) for forming an ink receiving layer was prepared by using a PET film (Toray Industries, Inc .: Lumirror T-100,
It is applied with a bar coater (# 60) to a thickness of 100 μm, a refractive index of 1.65, a base material transmittance of 88.0%, a haze of 1.0% and a reflectance of 5.1%, and dried at 40 ° C. for 10 minutes. Then, a recording sheet (7) with an ink receiving layer was prepared by heat treatment at 60 ° C. for 30 minutes. At this time, the thickness of the ink receiving layer was 10 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorption and gas barrier properties of the obtained recording sheet with ink receiving layer (7) were evaluated. The results are shown in Table 1.
[Example 8]
Preparation of swellable resin particle (4) dispersion A water-soluble acrylic polymer (A) solution having a solid content of 17% by weight was prepared in the same manner as in Example 1.

Next, while adding t-butyl (meth) acrylate (B) as an anionic solvent containing an acrylic ester group to a water-soluble acrylic polymer (A) solution having a solid content of 17% by weight, a hydroxyl group was added. As the vinyl ether group, 2-hydroxyethyl vinyl ether (C
) At the same time as (B) at a molar ratio of 1: 3 with respect to t-butyl acrylate. Furthermore, 4 g of an acrylic surfactant (manufactured by NOF Corporation: SUNBRIGHT, PA series, solid concentration 40 wt%, dispersion medium: water, pH 8.0), which is a glycol (PEG) derivative, was added.
Stir at 20 ° C. for 20 minutes. The addition of (B) and (C) was performed until PH became 7.

  Subsequently, coarse particles and foreign matters were filtered and removed with a filter having a pore diameter of 1 μm, and finally, a swellable resin particle (4) dispersion having a solid content concentration of 15.0% by weight was prepared by adjusting the concentration. The weight average particle diameter of the obtained swellable resin particles (4) is shown in the table.

Preparation of coating liquid (8) for forming ink receiving layer 10 g of the swellable resin particle (4) dispersion obtained above and alumina hydrate adjusted to a solid content concentration of 15% by weight as inorganic fine particles. Particles (1) 10 g of dispersion, 4 g of polymerizable unsaturated monomer containing carboxylic acid as polymerizable unsaturated monomers (manufactured by Shin Nippon Rika Co., Ltd .: Rikajit BT-W), acrylic resin fine particles (Tojo) as polymer resin Synthetic Chemical Co., Ltd .: UC-3510 (3.0 g) and a carbodiimide compound (Nisshinbo Co., Ltd .: Carbodilite V-02) 0.25 g as a cross-linking agent were mixed well and an ink receiving layer forming coating solution (8 ) Was prepared.

Preparation of recording sheet with ink receiving layer (8) In Example 1, ink receiving layer was formed in the same manner as in Example 1, except that the ink receiving layer forming coating solution (8) was used instead of the ink receiving layer forming coating solution (1). A layered recording sheet (8) was prepared. At this time, the thickness of the ink receiving layer was 10 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorptivity and gas barrier properties of the obtained recording sheet with an ink receiving layer (8) were evaluated. The results are shown in Table 1.
[Example 9]
Preparation of Alumina Hydrate Particles (2) A sodium hydroxide aqueous solution with a concentration of 5% by weight was added dropwise to 1000 g of a 3% by weight aluminum chloride aqueous solution to adjust the pH to 7. Then, it stirred at 25 degreeC for 1 hour, and obtained the alumina hydrate gel. The obtained gel was subjected to suction filtration with a 10 μm polypropylene filter, separated into solid and liquid, and washed with 2000 g of 60 ° C. hot water.

  The obtained washing gel had a concentration of 12% by weight as a solid content. To this washing gel, ammonia water with a concentration of 10% by weight was added to adjust the pH to 9, and after aging at 100 ° C. for 60 hours, nitric acid with a concentration of 10% by weight was added to adjust the pH to 3.5, and at 120 ° C. for 2 hours. Drying gave alumina hydrate particles (2).

The crystal structure, average primary particle diameter, average secondary particle diameter, average pore diameter and pore volume of the obtained alumina hydrate particles (2) by X-ray diffraction are shown in the table.
Preparation of Ink Receptive Layer Forming Coating Liquid (9) In Example 1, except that 154 g of alumina hydrate particle (2) dispersion liquid adjusted to a solid content concentration of 15.0% by weight as inorganic fine particles was used. A coating liquid (9) for forming an ink receiving layer was prepared.
Preparation of recording sheet with ink-receiving layer (9) In Example 1, ink receiving layer was similarly prepared except that the ink-receiving layer-forming coating solution (9) was used instead of the ink-receiving layer-forming coating solution (1). A layered recording sheet (9) was prepared. At this time, the thickness of the ink receiving layer was 10 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorbability and gas barrier properties of the obtained recording sheet with an ink receiving layer (9) were evaluated, and the results are shown in Table 1.
[Example 10]
Preparation of Alumina Hydrate Particles (3) A sodium hydroxide aqueous solution having a concentration of 5% by weight was added dropwise to 1000 g of a 3% by weight aluminum chloride aqueous solution to adjust the pH to 7. Then, it stirred at 25 degreeC for 1 hour, and obtained the alumina hydrate gel. The obtained gel was subjected to suction filtration with a 10 μm polypropylene filter, separated into solid and liquid, and washed with 2000 g of 60 ° C. hot water.
The obtained washing gel had a concentration of 12% by weight as a solid content. To this washing gel, ammonia water with a concentration of 10% by weight was added to adjust the pH to 9, and after aging at 100 ° C. for 150 hours, nitric acid with a concentration of 10% by weight was added to adjust the pH to 3.5, and then at 120 ° C. for 2 hours. Drying gave alumina hydrate particles (3).

The crystal structure, average primary particle diameter, average secondary particle diameter, average pore diameter, and pore volume of the obtained alumina hydrate particles (3) by X-ray diffraction are shown in the table.
Preparation of Ink-Receptive Layer Forming Coating Liquid (10) In Example 1, the same procedure was used except that 10 g of the alumina hydrate particle (3) dispersion adjusted to a solid content concentration of 15.0% by weight was used as the inorganic fine particles. A coating liquid (10) for forming an ink receiving layer was prepared.
Preparation of recording sheet with ink receiving layer (10) In Example 1, ink receiving layer was similarly prepared except that the ink receiving layer forming coating solution (10) was used instead of the ink receiving layer forming coating solution (1). A layered recording sheet (10) was prepared. At this time, the thickness of the ink receiving layer was 10 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorptivity and gas barrier property of the obtained recording sheet with an ink receiving layer (10) were evaluated, and the results are shown in Table 1.
[Example 11]
Preparation of Magnesium Oxide Hydrate (1) The pH was adjusted to 9 by adding dropwise a 5 wt% sodium hydroxide aqueous solution to 1000 g of a 3 wt% magnesium chloride aqueous solution. Then, it stirred at 25 degreeC for 1 hour, and the magnesium hydroxide hydrate gel was obtained. The obtained gel was subjected to suction filtration with a 10 μm polypropylene filter, separated into solid and liquid, and washed with 2000 g of 60 ° C. warm water. The obtained washing gel had a solid content concentration of 15% by weight. Aqueous ammonia having a concentration of 10% by weight was added to the washing gel to adjust the pH to 10 and aged at 100 ° C. for 10 hours to obtain a magnesium oxide hydrate particle (1) dispersion having a solids concentration of 15% by weight. . The average primary particle diameter, average secondary particle diameter, crystal structure, average pore diameter by nitrogen adsorption, and pore volume of the obtained particles were measured under the conditions of Example 1. The results are shown in Table 1.
Preparation of Ink Receptive Layer Forming Coating Liquid (11) Ink was prepared in the same manner as in Example 1 except that 10 g of magnesium oxide hydrate particles (1) adjusted to a solid content concentration of 15.0% by weight were used as inorganic fine particles. Receiving layer forming coating solution (11)
Was prepared.
Preparation of recording sheet with ink receiving layer (11) In Example 1, ink receiving layer was similarly treated except that the ink receiving layer forming coating solution (11) was used instead of the ink receiving layer forming coating solution (1). A layered recording sheet (11) was prepared. At this time, the thickness of the ink receiving layer was 10 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorptivity and gas barrier properties of the obtained recording sheet with ink-receiving layer (11) were evaluated. The results are shown in Table 1.
[Example 12]
Preparation of coating liquid for forming ink receiving layer (12) In Example 1, silica alumina fine particles diluted to a solid concentration of 15.0% by weight as inorganic fine particles (manufactured by JGC Catalysts & Chemicals: FC200 Super, SiO ₂ / Al ₂ O ₃ = 30/1, average primary particle diameter 12 nm, average secondary particle diameter 25 nm, average pore diameter 8 nm, pore volume 0.3 cc / g) In the same manner, except for using 10 g, a coating solution for forming an ink receiving layer (12 ) Was prepared.
Preparation of recording sheet with ink-receiving layer (12) In Example 1, ink receiving layer was similarly prepared except that the ink-receiving layer-forming coating solution (12) was used instead of the ink-receiving layer-forming coating solution (1). A layered recording sheet (12) was prepared. At this time, the thickness of the ink receiving layer was 10 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorptivity and gas barrier properties of the obtained recording sheet with an ink receiving layer (12) were evaluated, and the results are shown in Table 1.
[Example 13]
Preparation of coating liquid for forming ink-receiving layer (13) In Example 1, 30 g of swellable resin particle (1) dispersion and alumina hydrate particle (1) dispersion adjusted to a solid content concentration of 15% by weight as inorganic fine particles 5 g of liquid, 1 g of polymerizable unsaturated monomer 2-hydroxyethyl acrylate (manufactured by Shin Nippon Rika Co., Ltd .: Rikajit BT-W) containing carboxylic acid as polymerizable unsaturated monomers, acrylic resin fine particles (as polymer resin) 1 g of Toagosei Chemical Co., Ltd .: UC-3510) and 0.2 g of a carbodiimide compound (Nisshinbo Co., Ltd .: Carbodilite V-02) as a cross-linking agent were mixed well and the coating solution for forming an ink receiving layer (13) Was prepared. Table 1 shows the results of properties of the resulting coating liquid (1) for forming an ink receiving layer.
Preparation of recording sheet with ink receptive layer (13) In Example 1, ink receptivity was similarly obtained except that the ink receptive layer forming coating liquid (13) was used instead of the ink receptive layer forming coating liquid (1). A layered recording sheet (13) was prepared. At this time, the thickness of the ink receiving layer was 10 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorptivity and gas barrier properties of the obtained recording sheet with an ink receiving layer (12) were evaluated, and the results are shown in Table 1.
[Comparative Example 1]
Preparation of coating liquid (R1) for forming ink-receiving layer As inorganic fine particles, 10 g of alumina hydrate particles (1) dispersion prepared in the same manner as in Example 1 and adjusted to a solid content concentration of 15% by weight, as a matrix-forming component 3 g of polyvinyl alcohol diluted with pure water to a concentration of 10% by weight (manufactured by Kuraray Co., Ltd .: PVA117) and 1 g of a boric acid aqueous solution with a concentration of 3% by weight as a curing agent were mixed well and a coating solution for forming an ink receiving layer ( R1) was prepared.

Preparation of recording sheet with ink-receiving layer (R1) Coating liquid (R1) for forming an ink-receiving layer was obtained by using a PET film (Toray Industries, Inc .: Lumirror T-100, thickness 100 μm, refractive index 1.65, substrate transmission) (88.0%, Haze 1.0%, reflectance 5.1%) with a bar coater (# 70) and heat-treated at 60 ° C. for 20 minutes to form a recording sheet (R1) with an ink receiving layer. Prepared. At this time, the thickness of the ink receiving layer was 10 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, light resistance and gas barrier properties of the obtained recording sheet with ink-receiving layer (R1) were evaluated, and the results are shown in Table 1.
[Comparative Example 2]
Preparation of coating liquid for forming ink-receiving layer (R2) 10 g of swellable resin particle (1) dispersion prepared in the same manner as in Example 1, and polymerizable unsaturated monomer containing carboxylic acid as polymerizable unsaturated monomers (New Nippon Rika Co., Ltd .: Rekajit BT-W) 8.2g, Polymer resin resin acrylic resin fine particles (Toagosei Chemical Co., Ltd .: UC-3510) 5.8g, Crosslinker carbodiimide compound (Nisshinbo ( Co., Ltd .: Carbodilite V-02) 0.2 g was mixed well to prepare an ink receiving layer forming coating solution (R2).

Preparation of recording sheet with ink-receiving layer (R2) In Example 1, ink receiving layer was similarly treated except that the ink-receiving layer-forming coating solution (R2) was applied instead of the ink-receiving layer-forming coating solution (1). A layered recording sheet (R2) was prepared. At this time, the thickness of the ink receiving layer was 10 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, ink absorptivity and gas barrier properties of the obtained recording sheet with ink receiving layer (R2) were evaluated. The results are shown in Table 1.
[Comparative Example 3]
Preparation of coating liquid for forming ink receiving layer (R3) In the same manner as in Example 1, a water-soluble acrylic polymer (A) solution having a solid concentration of 17% by weight as core particles was prepared.

Next, 10 g of water-soluble acrylic polymer (A) solution and solid content concentration 1 as inorganic fine particles
Alumina hydrate particles adjusted to 5% by weight (1) 10 g dispersion, polymerizable unsaturated monomer containing carboxylic acid as polymerizable unsaturated monomer (manufactured by Shin Nippon Rika Co., Ltd .: Rekagit BT-W) 4 0.0 g, 3.0 g of acrylic resin fine particles (manufactured by Toagosei Chemical Co., Ltd .: UC-3510) as a polymer resin, and 0.1 g of carbodiimide compound (Nisshinbo Co., Ltd .: Carbodilite V-02) as a crosslinking agent By mixing, a coating solution (R3) for forming an ink receiving layer was prepared.

Preparation of recording sheet with ink-receiving layer (R3) Coating liquid (R3) for forming an ink-receiving layer was prepared by PET film (Toray Industries, Inc .: Lumirror T-100, thickness 100 μm, refractive index 1.65, substrate transmission (88.0%, Haze 1.0%, reflectance 5.1%) with a bar coater (# 150) and heat-treated at 60 ° C. for 20 minutes to form a recording sheet (R3) with an ink receiving layer. Prepared. The thickness of the ink receiving layer at this time was 35 μm.

The total light transmittance, haze, adhesion, scratch resistance, water resistance, light resistance and gas barrier property of the obtained recording sheet with ink receiving layer (R3) were evaluated. The results are shown in Table 1.
[Comparative Example 4]
Preparation of Alumina Hydrate (4) A sodium hydroxide aqueous solution with a concentration of 5% by weight was added dropwise to 1000 g of a 3% by weight aluminum chloride aqueous solution to adjust the pH to 7. Then, it stirred at 25 degreeC for 1 hour, and obtained the alumina hydrate gel. The obtained gel was subjected to suction filtration with a 10 μm polypropylene filter, separated into solid and liquid, and washed with 2000 g of 60 ° C. hot water.
The obtained washing gel had a concentration of 12% by weight as a solid content. To this washing gel, ammonia water with a concentration of 10% by weight was added to adjust the pH to 9, and after aging at 200 ° C. for 60 hours, nitric acid with a concentration of 10% by weight was added to adjust the pH to 3.5, and then at 120 ° C. for 2 hours Drying gave alumina hydrate particles (4).

The crystal structure, average primary particle diameter, average secondary particle diameter, average pore diameter and pore volume of the obtained alumina hydrate particles (4) by X-ray diffraction are shown in the table.
Preparation of coating liquid for forming ink-receiving layer (R4) In Example 1, the same procedure was used except that 10 g of the alumina hydrate particle (4) dispersion liquid adjusted to a solid content concentration of 15.0% by weight was used as the inorganic fine particles. Ink-receiving layer forming coating solution (R4)
Was prepared.

Preparation of recording sheet with ink-receiving layer (R4) Coating liquid (R4) for forming an ink-receiving layer was obtained by using a PET film (Toray Industries, Inc .: Lumirror T-100, thickness 100 μm, refractive index 1.65, substrate transmission) (88.0%, Haze 1.0%, reflectance 5.1%) with a bar coater (# 150) and heat-treated at 60 ° C. for 20 minutes to form a recording sheet (R4) with an ink receiving layer. Prepared. At this time, the thickness of the ink receiving layer was 10 μm.

  The total light transmittance, haze, adhesion, scratch resistance, water resistance, light resistance and gas barrier property of the obtained recording sheet with an ink receiving layer (R4) were evaluated. The results are shown in Table 1.

Claims (18)

It consists of swellable resin particles having a core cell structure having a cell layer made of a swellable resin, polymerizable unsaturated monomers, a polymer resin, a crosslinking agent, inorganic fine particles, and a dispersion medium.
The average primary particle diameter measured by the TEM observation method of the inorganic fine particles is in the range of 1 to 200 nm, and the pore volume (PV _N ) measured by the nitrogen adsorption method is in the range of 0.1 to 2.0 cc / g. The average pore diameter is in the range of 5 to 60 nm, the total solid content concentration is in the range of 1 to 50% by weight,
The concentration of the swellable resin particles is in the range of 0.05 to 40% by weight as the solid content,
The concentration of the polymerizable unsaturated monomers is in the range of 0.01 to 20% by weight as a solid content,
The concentration of the polymer resin is in the range of 0.01 to 10% by weight as the solid content,
The concentration of the crosslinking agent is in the range of 0.001 to 10% by weight as a solid content,
A coating liquid for forming an ink receiving layer, wherein the concentration of inorganic fine particles is in the range of 0.01 to 45% by weight as a solid content. The inorganic fine particles are MgO, TiO ₂ , SiO ₂ , ZrO ₂ , Al ₂ O ₃ , Sb ₂ O ₅ , ZnO.
And at least one selected from the group consisting of these complex oxides, and an average particle size measured by a dynamic light scattering method is in the range of 5 to 10,000 nm. Coating liquid for forming an ink receiving layer.   3. The coating liquid for forming an ink receiving layer according to claim 1, wherein the inorganic fine particles are pseudo boehmite alumina and / or boehmite alumina.   The ink receiving layer forming coating solution according to claim 1, wherein the inorganic fine particles have a chain structure.   The coating liquid for forming an ink receiving layer according to claim 1, wherein the swellable resin particles have an average particle diameter in the range of 20 to 500 nm.   6. The ink according to claim 1, wherein the core of the swellable resin particle is made of one or more kinds of resins selected from acrylic resin fine particles, urethane resin fine particles, and vinyl resin fine particles. Coating solution for forming a receiving layer.   7. The ink receiving layer according to claim 1, wherein the swellable resin constituting the cell layer of the swellable resin particles includes a polymer main chain derived from a (meth) acrylic resin. Coating liquid for forming.   The swelling resin constituting the cell layer has a carboxyl group, a carbonyl group, a hydroxyl group, an amino group, a halogen group, a urethane group, an alkyl group, a phenyl group, a sulfone group, an alkoxyl group, a thiol group, and a side chain or a terminal. The coating liquid for forming an ink receiving layer according to claim 1, comprising at least one functional group selected from the group consisting of cyano groups.   9. The ink receiving layer forming coating liquid according to claim 1, wherein the crosslinking agent is at least one selected from a carbodiimide compound, a cyano compound, a melamine compound, an oxozaline compound, and an isocyanate compound. (i) polymerizable unsaturated monomers are a carboxyl group, a carbonyl group, a hydroxyl group, an amino group,
(Meth) acrylic resins and organic acid vinyl ester resins having one or more functional groups selected from the group consisting of halogen groups, urethane groups, alkyl groups, phenyl groups, sulfone groups, alkoxyl groups, vinyl groups, and thiol groups , Vinyl ether resins, halogen-containing resins, ester resins, amide resins, urethane resins, cellulose derivatives,
(ii) The group in which the polymer resin is composed of acrylic resin fine particles, urethane resin fine particles, polyvinyl alcohol resin fine particles, vinyl resin fine particles, ethylene resin fine particles, polystyrene resin fine particles, ester resin fine particles, and epoxy resin fine particles. The coating liquid for forming an ink receiving layer according to claim 1, wherein the coating liquid is one or more selected from the group consisting of: A base sheet and an ink receiving layer formed on the base sheet;
The ink receiving layer is composed of swellable resin particles having a core cell structure, a resin matrix and inorganic fine particles,
The cell layer of the swellable resin particles is made of a swellable resin,
The swelling resin of the cell layer and the resin matrix have a crosslinked network structure,
The average primary particle diameter measured by the TEM observation method of the inorganic fine particles is in the range of 1 to 200 nm,
The pore volume (PV _N ) measured by the nitrogen adsorption method is in the range of 0.1 to 2.0 cc / g, the average pore diameter is in the range of 5 to 60 nm,
Ink receiving, wherein the pore volume (PV _Hg ) of the ink receiving layer measured by mercury intrusion method is in the range of 0.01 to 1.4 cc / g and the average pore diameter is in the range of 5 to 40 nm. Layered recording sheet. The water absorption amount (PV _H2O ) of the ink receiving layer is in the range of 0.1 to 2.0 cc / g, and the ratio of the water absorption amount (PV _H2O ) to the pore volume (PV _Hg ) (PV _H2O) / (PV _Hg) recording sheets with an ink-receiving layer according to claim 11, characterized in that in the range of 1.4 to 100. The inorganic fine particles are MgO, TiO ₂ , SiO ₂ , ZrO ₂ , Al ₂ O ₃ , Sb ₂ O ₅ , ZnO.
And at least one selected from the group consisting of these complex oxides, wherein the average particle size measured by a dynamic light scattering method is in the range of 5 to 10,000 nm. A recording sheet with an ink-receiving layer as described in 1.   The recording sheet with an ink receiving layer according to claim 11, wherein the inorganic fine particles are pseudo boehmite alumina and / or boehmite alumina.   The recording sheet with an ink receiving layer according to claim 11, wherein the inorganic fine particles have a chain structure.   The ink according to any one of claims 11 to 15, wherein the core portion of the swellable resin particle is made of one or more kinds of resins selected from acrylic resin fine particles, urethane resin fine particles, and vinyl resin fine particles. Recording sheet with receptor layer.   The ink receiving layer is obtained by applying the coating liquid according to any one of claims 1 to 10 on a substrate sheet, followed by drying and heating. A recording sheet with an ink receiving layer according to claim 1. The swellable resin constituting the cell layer of the swellable resin particles contains a polymer main chain derived from a (meth) acrylic resin, and has a carboxyl group, a carbonyl group, a hydroxyl group, an amino group, a halogen at the side chain or terminal. Including one or more functional groups selected from the group consisting of a group, a urethane group, an alkyl group, a phenyl group, a sulfone group, an alkoxyl group, a thiol group, and a cyano group,
A resin matrix (i) a polymer component derived from polymerizable unsaturated monomers; and (ii)
18. The recording sheet with an ink receiving layer according to claim 11, comprising a polymer resin and (iii) crosslinked together with a swellable resin of a cell layer by a crosslinking agent.