JP2016016529A - Recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording medium having excellent glossiness and high adhesiveness between an ink receiving layer and a support body.SOLUTION: A recording medium includes a resin-coated support body 100 provided with a resin layer 102 on a base paper 101, a lower layer 103, and an ink receiving layer 104 adjacent to each other in this order. The surface of the resin layer has an arithmetic average roughness Ra specified in JISB0601:2001 of 0.2 or less. The lower layer comprises polyvinyl alcohol and particles 105 having an average particle diameter of 0.5 μm or more and 15.0 μm or less. The ratio of the average particle diameter of the particles to the average thickness of the lower layer is 0.8 or more and 50.0 or less. The content of the particles in the lower layer is 0.001 g/mor more and 0.1 g/mor less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a recording medium, and preferably to an inkjet recording medium.

  Ink jet recording media are required to have characteristics such as high printing density (good color developability) and uniform absorption of ink (good absorbency). Also, in the recent commercial printing field, for example, on-demand photo collections consisting of photos with mixed favorite photos or characters, that is, booklets such as photo books and photo albums are bound. Along with this, there is a demand for an inkjet recording medium having excellent gloss.

  In order to obtain an inkjet recording surface having high gloss, it is effective to use a smooth support. For example, in Patent Document 1, a support in which both sides of paper are coated with a polyolefin resin is used. . In the ink jet recording paper described in Patent Document 1, an undercoat layer mainly composed of a hydrophilic polymer and a porous ink absorbing layer are provided in this order on the support. Further, the surface of the polyolefin resin coating layer on the side where the porous ink absorbing layer is provided is subjected to fine roughening. The 75 degree specular glossiness of the surface of the undercoat layer is 30 to 80%.

JP 2004-284146 A

  As described above, in order to obtain a recording medium having high gloss, it is effective to use a support made of a base paper coated with a resin. However, when an ink receiving layer is provided on a support made of a resin-coated base paper, particularly a support having a smooth resin layer, the adhesion between the ink receiving layer and the support tends to decrease. . As a result, when stress such as bending is applied, a problem may occur in the adhesion between the ink receiving layer and the support.

  Accordingly, an object of the present invention is to provide a recording medium having excellent gloss and high adhesion between the ink receiving layer and the support.

The present invention
A recording medium having a resin-coated support provided with a resin layer on a base paper, a lower layer, and an ink receiving layer adjacent to each other in this order,
The arithmetic average roughness Ra defined by JIS B 0601: 2001 on the surface of the resin layer is 0.2 or less,
The lower layer includes polyvinyl alcohol and particles having an average particle size of 0.5 μm or more and 15.0 μm or less,
The ratio of the average particle diameter of the particles to the average film thickness of the lower layer is 0.8 or more and 50.0 or less,
The recording medium is characterized in that the content of the particles in the lower layer is 0.001 g / m ² or more and 0.1 g / m ² or less.

  According to the configuration of the present invention, it is possible to provide a recording medium having excellent gloss and high adhesion between the ink receiving layer and the support.

It is a typical sectional view showing an example of composition of a recording medium of this embodiment.

  Embodiments of the present invention will be described below.

FIG. 1 is a schematic cross-sectional view illustrating a configuration example of a recording medium according to the present embodiment. The recording medium according to the present embodiment includes a resin-coated support body 100 including a base paper 101 and a resin layer 102 formed on the base paper. That is, the recording medium has a resin-coated support in which a resin layer is provided on a base paper, a lower layer, and an ink receiving layer, which are adjacent to each other in this order. The recording medium according to the present embodiment includes a lower layer 103 formed on the resin layer 102 of the resin-coated support in contact with the resin layer, and an ink receiving unit formed on the lower layer in contact with the lower layer. Layer 104. Moreover, arithmetic mean roughness Ra prescribed | regulated by JISB0601: 2001 of the surface of the resin layer 102 is 0.2 or less. The lower layer 103 includes polyvinyl alcohol as a binder (hereinafter also referred to as a first binder), and particles (hereinafter also referred to as first particles) 105 having an average particle diameter of 0.5 μm or more and 15.0 μm or less, including. The ratio of the average particle diameter of the particles to the average film thickness of the lower layer 103 is 0.8 or more and 50.0 or less. Further, the content of particles in the lower layer 103 is 0.001 g / m ² or more and 0.1 g / m ² or less.
When the Ra of the resin layer surface is 0.2 or less, the resin layer surface becomes smooth and has an advantage of improving glossiness, while the adhesion to the ink receiving layer provided on the resin layer is lowered. The ink-receiving layer is easily peeled off by stress such as bending. Therefore, in the present invention, the lower layer contains particles having an average particle size of 0.5 μm or more and 15.0 μm or less, and the ratio of the average particle size of the particles to the average film thickness of the lower layer and the content of the particles in the lower layer are respectively determined. By setting the predetermined range, the interface between the lower layer and the ink receiving layer can be roughened. For this reason, the contact area through the lower layer between the ink receiving layer and the resin-coated support increases, so that the adhesion can be improved.

  Hereinafter, the components of the present invention will be described.

<Resin-coated support>
The resin-coated support is composed of a base paper and a resin layer formed on the base paper.

  The resin layer is preferably formed on both sides of the base paper. Examples of the resin-coated support include resin-coated paper in which both surfaces of a base paper are coated with a resin. The base paper is not particularly limited, and generally used paper can be used. The base paper is preferably a smooth base paper used for a photographic support. Examples of the pulp constituting the base paper include natural pulp, recycled pulp, synthetic pulp, and the like. These may be used alone or in combination of two or more. This base paper can be blended with additives such as sizing agent, paper strength enhancing agent, filler, antistatic agent, fluorescent brightening agent, and dye generally used in papermaking. Furthermore, a surface sizing agent, a surface paper strength agent, a fluorescent whitening agent, an antistatic agent, a dye, an anchor agent, and the like may be applied to the surface of the base paper.

  The thickness of the base paper is preferably 50 μm or more. When the thickness of the base paper is 50 μm or more, the strength against pulling and tearing can be increased, and the texture can be improved. The thickness of the base paper is preferably 350 μm or less. When the thickness of the base paper is 350 μm or less, the handleability of the recording medium can be improved.

As the base paper, those subjected to a surface treatment such as compressing by applying pressure with a calendar or the like during paper making or after paper making are preferable. Such surface treatment can improve surface smoothness. The density of the base paper is preferably 0.6 g / cm ³ or more and 1.2 g / cm ³ or less. When the density of the base paper is 1.2 g / cm ³ or less, the cushioning property can be improved and the transportability can be improved. Further, when the density of the base paper is 0.6 g / cm ³ or more, the surface smoothness can be improved. The density of the base paper is more preferably 0.7 g / cm ³ or more.

  The arithmetic average roughness Ra defined by JIS B 0601: 2001 on the surface of the resin layer is preferably 0.2 μm or less and more preferably 0.15 μm or less from the viewpoint of gloss.

  The thickness of the resin layer can be determined as appropriate from the curl property related to the thickness of the base paper, and is preferably 5 μm or more and 50 μm or less, more preferably 8 μm or more and 40 μm or less. When the thickness of the resin coating layer is 5 μm or more, water and gas permeation from the resin surface can be suppressed, and cracking of the ink receiving layer due to bending can be suppressed. Moreover, when the thickness of the resin coating layer is 50 μm or less, curling resistance can be improved, and handling properties can be improved.

  The kind of resin used for the resin layer is not particularly limited, and examples thereof include polyethylene and polypropylene. Examples of polyethylene include low density polyethylene (LDPE) and high density polyethylene (HDPE). Examples of the low density polyethylene include linear low density polyethylene (LLDPE).

  The resin layer may contain additives such as rutile or anatase type titanium oxide, fluorescent whitening agent, ultramarine, etc., as widely used for photographic paper. By adding an additive to the resin, the opacity, whiteness and hue can be improved. The content of titanium oxide in the resin layer is preferably 3 parts by mass or more and 20 parts by mass or less, and preferably 4 parts by mass or more and 13 parts by mass or less with respect to 100 parts by mass of the resin in the resin coating layer. More preferred.

  The surface state of the resin-coated support, that is, the surface state of the resin layer is, for example, a cooling that has been subjected to various surface treatments such as mirror surface treatment and rough surface treatment when the resin is melt extruded onto the base paper surface and coated. It can be controlled by pressing the roll against the surface of the resin layer.

  The 60 ° glossiness of the surface of the support is preferably 65% or more, more preferably 70% or more, and further preferably 80% or more. When the 60 ° glossiness of the surface of the support is 65% or more, a recording medium having excellent glossiness can be provided.

<Lower layer>
The lower layer contains polyvinyl alcohol as a first particle having an average particle diameter of 0.5 μm or more and 15.0 μm or less and a binder. The lower layer is formed in contact with the resin layer. That is, the lower layer is formed between the resin layer and the ink receiving layer in contact with the resin layer and the ink receiving layer. The lower layer has a structure in which the particles are embedded in a continuous film formed of the polyvinyl alcohol.

  The first particles contained in the lower layer are not particularly limited, and examples thereof include inorganic particles and resin particles. Examples of inorganic particles include alumina, alumina hydrate, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, and wet silica. Or magnesium hydroxide. Examples of the resin particles include polymethyl methacrylate resin, polystyrene resin, polycarbonate resin, polyacrylate resin, polyacrylic acid resin, starch, polyethylene resin, silicon resin, phenol resin, fluorine resin, polyester resin, polyamide resin, polyphenylene oxide resin. And particles of thermoplastic resins such as vinyl chloride resin, fluororesin, vinyl acetate resin, and silicone rubber, urethane resin, melamine resin, silicon resin, butyral resin, phenol resin, epoxy resin, and unsaturated polyester resin. These may be used singly or in combination of two or more.

  As the first particles, wet silica is preferable from the viewpoint of improving the adhesion of the ink receiving layer. As wet silica, precipitation method silica or gel method silica is preferably mentioned. Precipitated silica can be produced, for example, by reacting sodium silicate and sulfuric acid under alkaline conditions. Silica particles on which the particles have grown during the production process are aggregated and settled, and then processed through filtration, washing, drying, pulverization and classification. The silica secondary particles produced by this method are agglomerated particles that are relatively easily pulverized. Examples of the precipitated silica are commercially available from Tosoh Silica Co., Ltd. as nip seal (trade name), from Tokuyama Co., Ltd. as Toku Seal, and fine seal (both trade names). The gel method silica can be produced, for example, by reacting sodium silicate and sulfuric acid under acidic conditions. In the case of gel method silica, small silica particles are dissolved in the production process and re-precipitated so that primary particles of relatively large particles are bonded to each other, so that relatively hard aggregated particles having an internal void structure are formed. As the gel method silica, for example, it is commercially available from Mizusawa Chemical Industry Co., Ltd. as Mizukasil (trade name) and from Grace Japan Co., Ltd. as silo jet (trade name).

  The average particle diameter of the first particles is from 0.5 μm to 15.0 μm, preferably from 1.5 μm to 10.0 μm, and more preferably from 1.5 μm to 5.0 μm. When the average particle size of the first particles is 0.5 μm or more, the adhesion improving effect can be sufficiently obtained. When the average particle diameter of the first particles is 15.0 μm or less, it is possible to suppress a decrease in glossiness of the surface of the recording medium.

The content of the first particles in the lower layer (also referred to as abundance) is, 0.001 g / ^{m 2} or more 0.1 g / ^{m 2} or less, is 0.01 g / ^{m 2} or more 0.05 g / ^{m 2} or less It is preferable. When the content of the first particles is 0.001 g / m ² or more, an adhesion improving effect can be sufficiently obtained. When the content of the first particles is 0.1 g / m ² or less, it is possible to suppress a decrease in the glossiness of the surface of the recording medium.

  The average particle diameter of the first particles is a sphere equivalent particle diameter measured by an electrical resistance method in a pore based on the Coulter principle. The average particle diameter of the first particles can be measured using, for example, Multisizer 3 (manufactured by Beckman Coulter, Inc.).

  The lower layer contains polyvinyl alcohol as the first binder. Polyvinyl alcohol can be synthesized, for example, by hydrolyzing polyvinyl acetate. Among them, from the viewpoint of ink absorbability, completely or partially saponified polyvinyl alcohol or cation-modified polyvinyl alcohol is preferable. Furthermore, polyvinyl alcohol having an average polymerization degree of 2000 or more and a saponification degree of 85 mol% or more and 98 mol% or less is preferable from the viewpoint of water resistance and color developability. Furthermore, it is preferable that the weight average polymerization degree of polyvinyl alcohol is 2000 or more and 5000 or less. In addition, the saponification degree of polyvinyl alcohol is a value measured by the method of JIS-K6726. Chemically, the saponification degree is a ratio of the number of moles of hydroxyl groups generated by a saponification reaction when polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The average degree of polymerization of polyvinyl alcohol refers to the viscosity average degree of polymerization determined by the method described in JIS-K6726 (1994).

  Examples of the cation-modified polyvinyl alcohol include a polyvinyl alcohol having a primary to tertiary amino group or a quaternary ammonium group in the main chain or side chain of polyvinyl alcohol as described in JP-A-61-110483. Alcohol is preferred.

  Polyvinyl alcohol is preferably used in the form of an aqueous solution. The dry solid content of polyvinyl alcohol in the lower layer coating solution is preferably 3% by mass or more and 20% by mass or less. By setting the content of polyvinyl alcohol to 3% by mass, a decrease in the drying rate can be suppressed. Moreover, by making content of polyvinyl alcohol into 20 mass% or less, the excessive raise of a coating liquid viscosity can be suppressed and the smoothness of a coating surface can be improved.

  The lower layer can be formed by applying a lower layer coating solution on the resin layer of the resin-coated support. The lower layer coating liquid contains the above-mentioned first particles and polyvinyl alcohol, and can appropriately contain a solvent, an additive, and the like.

  Examples of the additive include a crosslinking agent, a fixing agent such as a cationic resin, an aggregating agent such as a polyvalent metal salt, a surfactant, a fluorescent whitening agent, a thickening agent, an antifoaming agent, a defoaming agent, and a release agent. Agents, penetrants, lubricants, ultraviolet absorbers, antioxidants, leveling agents, preservatives, pH adjusters and the like.

  Examples of the coating method for the lower layer coating liquid include, for example, an air knife coating method, a gravure coating method, a blade coating method, a bar coating method, a roll coating method, a rod bar coating method, a slot die coating method, a curtain coating method, and a size press. Law.

In the present invention, the ratio of the average particle diameter of the first particles to the average film thickness of the lower layer is 0.8 or more and 50.0 or less. That is, the average particle diameter of the first particles and the average film of the lower layer so that the average particle diameter of the first particles is in the range of 0.8 times to 50.0 times the average film thickness of the lower layer. Select the thickness to form the lower layer.
In the present invention, the cross section of the obtained recording medium is observed with an electron microscope, and 100 points where no first particles are present in the thickness direction (particle non-existing portion) are arbitrarily selected. The average value of the thickness is taken as the average film thickness of the lower layer.

In the present invention, the content of the first particles in the lower layer is 0.001 g / m ² or more and 0.1 g / m ² or less.

  Since the first particles are present at a relatively low concentration in the lower layer, when a cross section of the lower layer is observed, there is a portion where no particles exist (particle non-existing portion) in the thickness direction in the lower layer. The thickness of the particle non-existing portion (d in FIG. 1) can be adjusted by the binder content. The ratio of the average particle diameter of the first particles (average particle diameter of the first particles / average film thickness of the lower layer) to the average film thickness of the lower layer (also referred to as the average film thickness of the non-existing portion) is 0.8 or more and 50 By setting the ratio to 0.0 or less, the adhesion of the ink receiving layer can be improved. That is, by setting this ratio within this range, the protrusions due to the first particles in the lower layer become relatively large, and the adhesion of the ink receiving layer can be improved.

  The average thickness of the lower layer is preferably 0.1 μm or more and 3.0 μm or less. The content of the first binder in the lower layer is preferably adjusted so that the average film thickness of the lower layer is in the range of 0.1 μm to 3.0 μm. If the average film thickness of the lower layer is within this range, the adhesion of the ink receiving layer to the resin-coated support can be improved. Moreover, it is preferable that the average film thickness of a lower layer is 0.2 micrometer or more and 1.0 micrometer or less.

  The arithmetic average roughness Ra defined by JIS B 0601: 2001 on the surface of the lower layer is preferably 0.05 μm or more and 0.20 μm or less from the viewpoint of the effect of improving adhesion.

<Ink receiving layer>
The ink receiving layer is formed in contact with the lower layer. The ink receiving layer is preferably a porous ink receiving layer having voids in the layer from the viewpoint of ink absorbability. The porous type ink receiving layer may contain porous inorganic particles and a second binder (also referred to as an ink receiving layer binder).

  The ink receiving layer has a porous structure formed by porous inorganic particles. The inorganic particles are preferably at least one selected from gas phase method silica, alumina hydrate and alumina from the viewpoints of high speed absorption, dye fixing property, transparency, printing density and color developability.

  These inorganic fine particles preferably have a primary particle size of 50 nm or less, and it is preferable to use particles whose secondary particle size is atomized to 0.2 μm or less from the viewpoint of color developability and gloss.

  The second binder (also referred to as an ink receiving layer binder) contained in the ink receiving layer is not particularly limited, and for example, those exemplified as the lower layer binder can be used. The content of the second binder is preferably 50 parts by mass or less and more preferably 30 parts by mass or less with respect to 100 parts by mass of the inorganic particles from the viewpoint of ink absorbability. Further, from the viewpoint of binding the inorganic particles, the content of the second binder is preferably 5 parts by mass or more and more preferably 8 parts by mass or more with respect to 100 parts by mass of the inorganic particles.

  The ink receiving layer preferably contains a crosslinking agent capable of crosslinking the second binder, and the second binder is preferably crosslinked and cured. Since the second binder contained in the ink receiving layer is crosslinked, it is possible to prevent the second binder from swelling and clogging the pores during ink absorption, thereby suppressing a decrease in absorbability. be able to. Examples of the crosslinking agent include boric acid, borates, water-soluble zirconium compounds, and the like. Of these, boric acid and borates are preferred. In addition, examples of the crosslinking agent include aldehydes such as glyoxal. The content of the crosslinking agent is preferably 1 part by mass or more and 50 parts by mass or less, and preferably 5 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the second binder contained in the ink receiving layer. More preferred.

  The ink receiving layer may contain various additives as necessary. Examples of additives include fixing agents such as various cationic resins, aggregating agents such as polyvalent metal salts, surfactants, fluorescent whitening agents, thickening agents, antifoaming agents, antifoaming agents, release agents, Examples include penetrants, lubricants, ultraviolet absorbers, antioxidants, leveling agents, preservatives, and pH adjusters.

  The ink receiving layer can be formed by applying an ink receiving layer coating liquid on the lower layer. Have. More specifically, examples of the method for forming the ink receiving layer include the following methods. First, a coating liquid in which a pigment, a binder, a crosslinking agent, a pH adjuster, various additives, water, and the like are mixed as necessary is prepared for each layer. These coating liquids are coated on a support or a layer. The coating is performed on-machine or off-machine using, for example, various curtain coaters, a coater using an extrusion method, a coater using a slide hopper method, or the like. At the time of coating, for the purpose of adjusting the viscosity of each coating solution, the coating solution may be heated, or the coater head may be heated. Moreover, drying of the coating liquid after coating is performed using hot air dryers, such as a linear tunnel dryer, an arch dryer, an air loop dryer, a sine curve air float dryer, for example. Moreover, you may use the dryer etc. which utilized infrared rays, a heating dryer, a microwave, etc.

Note that one aspect of the present invention is
(1) preparing a resin-coated support composed of a base paper and a resin layer formed on the base paper;
(2) applying a lower layer coating solution containing polyvinyl alcohol and particles having an average particle size of 0.5 μm or more and 15.0 μm or less to the resin layer, and forming a lower layer;
(3) forming an ink receiving layer on the lower layer;
Have
The arithmetic average roughness Ra defined by JIS B 0601: 2001 on the surface of the resin layer is 0.2 or less,
The ratio of the average particle diameter of the particles to the average film thickness of the lower layer is 0.8 or more and 50.0 or less,
In the method for producing a recording medium, the content of the particles in the lower layer is 0.001 g / m ² or more and 0.1 g / m ² or less.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, the content of this invention is not restricted to an Example. “Part” or “%” means part by mass or mass% unless otherwise specified.

<Preparation of base paper A>
Base paper A was prepared by the following method.
First, a material having the following composition was adjusted with water so that the solid content concentration was 3.0% to prepare a paper stock.
Pulp 100 parts (freewood bleached kraft pulp (LBKP) (80 parts) with freeness 450 mlCSF (Canadian Standard Freeness) and softwood bleached kraft pulp (NBKP) (20 parts) with freeness 480 ml CSF)
・ Cationized starch 0.60 parts ・ Heavy calcium carbonate 10 parts ・ Light calcium carbonate 15 parts ・ Alkyl ketene dimer 0.10 parts ・ Cationic polyacrylamide 0.030 parts

Next, this stock was made with a long paper machine, subjected to a three-stage wet press, and then dried with a multi-cylinder dryer. Then, using the size press apparatus, it was made to impregnate the oxidized starch aqueous solution so that solid content might be 1.0 g / m < ² >, and it was made to dry. Thereafter, machine calendar finishing was performed to prepare a base paper A having a basis weight of 100 g / m ² .

<Preparation of dispersion>
(Preparation of wet silica dispersion 1)
To 80 parts of ion-exchanged water, 0.16 part of polyacrylic acid is added as a dispersant, and is rotated at 1500 rpm with a homomixer (made by Tokushu Kika Kogyo Co., Ltd., trade name: TK homomixer MARK II2.5 type). While stirring, 19.84 parts of precipitated silica particles having an average particle size of 2.6 μm (trade name: Fine Seal X-37, manufactured by Tokuyama Corporation) were added in small portions. After completion of the addition, the mixture was stirred for 30 minutes under the rotation condition of 1500 rpm to prepare wet silica particle dispersion 1 having a solid content concentration of 20% by mass.

(Preparation of wet silica dispersion 2)
Precipitation method silica particles having an average particle size of 1.5 μm (trade name: Fine Seal T-32, manufactured by Tokuyama Corporation) were added instead of the precipitation method silica particles (trade name: Fine Seal X-37, manufactured by Tokuyama Corporation). Except for the above, wet silica dispersion 2 (solid content concentration 20% by mass) was prepared in the same manner as wet silica dispersion 1.

(Preparation of wet silica dispersion 3)
Precipitation method silica particles having an average particle size of 6.2 μm (trade name: Fine Seal X-60, manufactured by Tokuyama Corporation) were added instead of the precipitation method silica particles (trade name: Fine Seal X-37, manufactured by Tokuyama Corporation). Except for the above, wet silica dispersion 3 (solid content concentration 20% by mass) was prepared in the same manner as wet silica dispersion 1.

(Preparation of wet silica dispersion 4)
Except that sedimentation method silica particles having an average particle size of 10 μm (trade name: Fine Seal X-12, manufactured by Tokuyama Corporation) were added instead of precipitation method silica particles (trade name: Fine Seal X-37, manufactured by Tokuyama Corporation). In the same manner as wet silica dispersion 1, wet silica dispersion 4 (solid content concentration 20% by mass) was prepared.

(Preparation of wet silica dispersion 5)
The wet silica dispersion 1 was further wet pulverized using a bead mill (zirconia beads having a diameter of 0.3 mm), the wet silica particles had an average particle size of 0.5 μm, and the wet silica dispersion 5 (solid content concentration 20% by mass) ) Was prepared.

(Preparation of wet silica dispersion 6)
Except for adding silica gel particles having an average particle diameter of 14 μm (trade name: NIPGEL BY-001, manufactured by Tosoh Silica) instead of sedimentation silica particles (trade name: Fine Seal X-37, manufactured by Tokuyama Corporation) In the same manner as in the wet silica dispersion 1, a wet silica dispersion 6 (solid content concentration 20% by mass) was prepared.

(Preparation of wet silica dispersion 7)
The wet silica dispersion 1 was further dispersed using a bead mill (0.1 mm diameter zirconia beads), the wet silica particles had an average particle size of 0.2 μm, and the wet silica dispersion 7 (solid content concentration 20 mass%) ) Was prepared.

(Preparation of resin particle dispersion 1)
Cross-linked polymethyl methacrylate particles having an average particle size of 5.0 μm (trade name: Techpolymer SSX-105, manufactured by Sekisui Plastics Co., Ltd.) instead of sedimentation method silica particles (trade name: Fine Seal X-37, manufactured by Tokuyama Corporation) ) Was added in the same manner as the wet silica dispersion 1 except that the resin particle dispersion 1 (solid content concentration 20% by mass) was prepared.

(Preparation of alumina hydrate dispersion 1)
To 333 parts of ion-exchanged water, 1.5 parts of methanesulfonic acid was added as peptizing acid. 100 parts of alumina hydrate (DISPERAL HP14, manufactured by Sasol) while stirring this aqueous methanesulfonic acid solution with a homomixer (trade name: TK. Was added in small portions. After completion of the addition, the mixture was stirred for 30 minutes under a rotation condition of 3000 rpm to prepare an alumina hydrate dispersion 1 having a solid content of 23%. The secondary particle size of the alumina hydrate particles in the obtained dispersion was 0.16 μm.

<Preparation of coating solution>
A coating solution for each layer was prepared by the following method.

(Lower layer coating solution 1)
-Wet silica dispersion 1 (solid content concentration 20%) 6.7 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 83.3 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed liquid so that it might become 0.1%, and the lower layer coating liquid 1 was prepared.

(Lower layer coating solution 2)
-Wet silica dispersion 1 (solid content concentration 20%) 1.3 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 96.7 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 2 was prepared.

(Lower layer coating solution 3)
-Wet silica dispersion 1 (solid content concentration 20%) 13.3 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 66.7 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 3 was prepared.

(Lower layer coating solution 4)
-Wet silica dispersion 1 (solid content concentration 20%) 0.13 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 99.70 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 4 was prepared.

(Lower layer coating solution 5)
-Wet silica dispersion 2 (solid content concentration 20%) 6.7 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 83.3 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 5 was prepared.

(Lower layer coating solution 6)
-Wet silica dispersion 3 (solid content concentration 20%) 6.7 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 83.3 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 6 was prepared.

(Lower layer coating solution 7)
-Wet silica dispersion 4 (solid content concentration 20%) 13.3 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 66.7 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 7 was prepared.

(Lower layer coating solution 8)
-Wet silica dispersion 5 (solid content concentration 20%) 13.3 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 66.7 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 8 was prepared.

(Lower layer coating solution 9)
・ Wet silica dispersion 1 (solid content 20%) 10 parts ・ Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 75 parts Water was added so that the solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed liquid so that it might become 0.1%, and the lower layer coating liquid 9 was prepared.

(Lower layer coating solution 10)
・ Wet silica dispersion 1 (solid content 20%) 2 parts ・ Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 95 parts Water was added so that the solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 10 was prepared.

(Lower layer coating solution 11)
Wet silica dispersion 1 (solid content concentration 20%) 0.7 part Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 98.3 parts These Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed liquid so that it might become 0.1%, and the lower layer coating liquid 11 was prepared.

(Lower layer coating solution 12)
-Wet silica dispersion 6 (solid content concentration 20%) 4 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 90 parts Water was added so that the solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 12 was prepared.

(Lower layer coating solution 13)
-Resin particle dispersion 1 (solid content concentration 20%) 6.7 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 83.3 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed liquid so that it might become 0.1%, and the lower layer coating liquid 9 was prepared.

(Lower layer coating solution 14)
・ Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray Co., Ltd., weight average polymerization degree 3500, saponification degree 88 mol%, solid content concentration 8%) 100 parts Add water to these materials so that the total solid content becomes 8%, and mix A liquid was prepared. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 14 was prepared.

(Lower layer coating solution 15)
-Wet silica dispersion 1 (solid content concentration 20%) 0.08 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 99.8 parts These Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 15 was prepared.

(Lower layer coating solution 16)
-Wet silica dispersion 7 (solid content concentration 20%) 6.7 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 83.3 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 16 was prepared.

(Lower layer coating solution 17)
-Wet silica dispersion 1 (solid content concentration 20%) 0.08 parts-Polyvinyl alcohol aqueous solution (PVA235, Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 99.00 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 17 was prepared.

(Lower layer coating solution 18)
-Wet silica dispersion 1 (solid content concentration 20%) 4.0 parts-Polyvinyl alcohol aqueous solution (PVA235, Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 50.0 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 18 was prepared.

(Lower layer coating solution 19)
-Wet silica dispersion 1 (solid content concentration 20%) 5.3 parts-Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 33.3 parts Water was added to the material so that the total solid content was 8% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so that it might become 0.1%, and the lower layer coating liquid 19 was prepared.

(Ink-receiving layer coating solution)
・ Alumina hydrate dispersion 1 (solid content 23%) 441 parts ・ Polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray, weight average polymerization degree 3500, saponification degree 88 mol%, solid content 8%) 125 parts ・ Orthoboric acid aqueous solution ( (5% solid content) 20 parts Water was added to these materials so that the total solid content was 18% to prepare a mixed solution. Surfactant (Surfinol 465) was added to this mixed solution so as to be 0.1% to prepare an ink receiving layer coating solution.

<Example 1>
A melt obtained by melting a polyethylene resin composition composed of low-density polyethylene (70 parts), high-density polyethylene (20 parts), and titanium oxide (10 parts) at 320 ° C. was formed so as to have a film thickness of 30 μm. Extrusion was applied to both sides of paper A. Next, the base paper A coated on both sides with the melt of the resin composition was transferred to a mirror-like cooling drum to obtain a resin-coated support having a smooth resin layer formed on both sides of the base paper A. . In addition, it was 0.13 micrometer when the arithmetic mean roughness Ra prescribed | regulated by JISB0601: 2001 of the surface of a resin layer was measured.
Next, corona discharge treatment was performed on both surfaces of the resin-coated support. Next, using a bar coater on both sides of the support, the lower layer coating solution 1 is applied so that the total coating amount (dry weight) is 0.3 g / m ² , dried with a hot air dryer, and the lower layer is coated. Formed. The 60 ° glossiness of the surface (resin layer surface) of the resin-coated support before applying the lower layer was 83%. In addition, the 60 degree glossiness of the lower layer surface was measured based on JISZ8741.

Next, using a slide die, the ink receiving layer coating solution was applied onto the lower layer so as to be 194 g / m ² and dried with a hot air dryer to form an ink receiving layer having a layer thickness of 35 μm. An ink jet recording medium was produced through the above steps.

<Example 2>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating liquid 1 used in Example 1 was changed to the lower layer coating liquid 2.

<Example 3>
An ink jet recording medium was produced in the same manner as in Example 1 except that the lower layer coating liquid 1 used in Example 1 was changed to the lower layer coating liquid 3.

<Example 4>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating liquid 1 used in Example 1 was changed to the lower layer coating liquid 4.

<Example 5>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating solution 1 used in Example 1 was changed to the lower layer coating solution 5.

<Example 6>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating liquid 1 used in Example 1 was changed to the lower layer coating liquid 6.

<Example 7>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating solution 1 used in Example 1 was changed to the lower layer coating solution 7.

<Example 8>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating liquid 1 used in Example 1 was changed to the lower layer coating liquid 8.

<Example 9>
An ink jet recording medium is prepared in the same manner as in Example 1 except that the lower layer coating liquid 1 used in Example 1 is changed to the lower layer coating liquid 9 and the dry coating amount of the lower layer is 0.2 g / m ^2. did.

<Example 10>
An ink jet recording medium is prepared in the same manner as in Example 1 except that the lower layer coating liquid 1 used in Example 1 is changed to the lower layer coating liquid 10 and the dry coating amount of the lower layer is 1.0 g / m ^2. did.

<Example 11>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating solution 1 used in Example 1 was changed to the lower layer coating solution 11 and the dry coating amount of the lower layer was changed to 3.0 g / m ^2. did.

<Example 12>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating solution 1 used in Example 1 was changed to the lower layer coating solution 12 and the dry coating amount of the lower layer was changed to 0.5 g / m ^2. did.

<Example 13>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating liquid 1 used in Example 1 was changed to the lower layer coating liquid 13.

<Comparative Example 1>
An ink jet recording medium was produced in the same manner as in Example 1 except that the lower layer was not formed.

<Comparative Example 2>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating solution 1 used in Example 1 was changed to the lower layer coating solution 14.

<Comparative Example 3>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating liquid 1 used in Example 1 was changed to the lower layer coating liquid 15.

<Comparative Example 4>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating liquid 1 used in Example 1 was changed to the lower layer coating liquid 16.

<Comparative Example 5>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating solution 1 used in Example 1 was changed to the lower layer coating solution 17 and the dry coating amount was 5.0 g / m ² .

<Comparative Example 6>
An ink jet recording medium was prepared in the same manner as in Example 1 except that the lower layer coating solution 1 used in Example 1 was changed to the lower layer coating solution 18 and the dry coating amount was 0.1 g / m ² .

<Comparative Example 7>
An ink jet recording medium was produced in the same manner as in Example 1 except that the lower layer coating solution 1 used in Example 1 was changed to the lower layer coating solution 19.

  Table 1 shows the results when manufactured by the above manufacturing method.

(Measurement method of the average thickness of the lower layer)
The cross section of the obtained recording medium is observed with an electron microscope, and 100 points where no first particles are present in the thickness direction are arbitrarily selected, and the average value of the 100 points is the average of the lower layer. The film thickness was taken.

<Evaluation method>
(Glossy)
The 20 ° glossiness of the surface of the ink receiving layer was measured based on JIS Z 8741, and judged according to the following criteria.
5: 20% or more 4: 16% or more and less than 20% 3: 13% or more and less than 16% 2: 10% or more and less than 13% 1: 10% or less.

(Adhesion)
After attaching Nichibansero tape (registered trademark) to the surface of the obtained recording medium with a metal roller, it was peeled off in the 90 ° direction, the peeled area of the ink receiving layer was confirmed, and judged according to the following criteria: .
5: Less than 10% 4: 10 or more but less than 20% 3: 20% or more but less than 30% 2: 30% or more but less than 50% 1: 50% or more.

DESCRIPTION OF SYMBOLS 100 Resin-coated support body 101 Base paper 102 Resin layer 103 Lower layer 104 Ink receiving layer 105 Particles (first particles)

Claims (5)

A recording medium having a resin-coated support provided with a resin layer on a base paper, a lower layer, and an ink receiving layer adjacent to each other in this order,
The arithmetic average roughness Ra defined by JIS B 0601: 2001 on the surface of the resin layer is 0.2 or less,
The lower layer includes polyvinyl alcohol and particles having an average particle size of 0.5 μm or more and 15.0 μm or less,
The ratio of the average particle diameter of the particles to the average film thickness of the lower layer is 0.8 or more and 50.0 or less,
The recording medium, wherein the content of the particles in the lower layer is 0.001 g / m ² or more and 0.1 g / m ² or less.   The recording medium according to claim 1, wherein the lower layer has a structure in which the particles are embedded in a continuous film formed of the polyvinyl alcohol.   The recording medium according to claim 1, wherein an arithmetic average roughness Ra defined by JIS B 0601: 2001 on the surface of the lower layer is 0.05 μm or more and 0.20 μm or less.   The recording medium according to claim 1, wherein an average film thickness of the lower layer is 0.1 μm or more and 3.0 μm or less.   The recording medium according to claim 1, wherein the particles are wet silica.

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