JP2001121810A - Ink jet recording sheet and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a homogeneous ink jet recording sheet having high maximum concentration, no craze and no image density unevenness and a method for manufacturing it. SOLUTION: The method for manufacturing an ink jet recording sheet comprises the step of coating a support with a surface energy larger than that of a coating liquid. The surface energy of the support is normally 35 to 55 mN/m(milli-Newton/meter). On the contrary, the surface energy of the coating liquid is smaller than that of the support and is preferred to a range of 30 to 50 mN/m. A difference of the energies of the support and the liquid is preferred to 2 to 5 mN/m. When these conditions are maintained, the dynamic surface tension of the liquid when coated is held to a preferred range, and uniform coating is conducted. Further, after coating, a craze in the step of concentrating and drying the liquid after coating is sufficiently suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a high concentration
The present invention relates to an ink jet recording paper and a method for producing the same, which realize high quality image quality.

[0002]

2. Description of the Related Art The ink jet recording system is a printing system for obtaining characters and images by directly ejecting and attaching ink droplets from a very fine nozzle to a non-printing medium. According to the ink jet recording method, not only has the advantage that the device to be used is low noise and has good operability, but also has the advantage that it is easy to colorize, and the use of plain paper can be widely used as a printing medium. It is widespread.

[0003] With the spread, the demand for high-quality recording has also increased, and accordingly, the image quality of ink-jet recording has been rapidly improved, and the image quality of the ink-jet recording has been approached without limit. Various improvements have been made to recording paper in order to realize such photographic image quality. One condition for achieving photographic image quality is an increase in the maximum density, and to increase this, it is necessary to increase the thickness of the ink jet recording layer. This is particularly necessary for a type of paper called a void type. In order to obtain photographic image quality, for example, the dry film thickness needs to be 30 μm or more, preferably 35 μm or more. When the film thickness is increased in this manner, cracks are likely to occur on the film surface. On the other hand, for example, Japanese Patent Application Laid-Open
Japanese Patent Application No. 0-44585 discloses a technique from the viewpoint of film properties such as adding a surfactant to a coating solution, but there is no disclosure of an improved technique by a production method at present. JP-A-10-
328613 and JP-A-11-147363, etc., disclose a manufacturing method, particularly a coating method, but this method is not sufficient to obtain a uniform ink jet recording sheet without cracks.

[0004] As a result of studying crack suppression from this viewpoint, by selecting various coating conditions,
It was found that cracks could be reduced.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a uniform ink jet recording paper having a high maximum density and free from cracks and image density unevenness, and a method for producing the same.

[0006]

The above object of the present invention is achieved by the following means. 1. A method for producing an ink jet recording paper, wherein the coating is performed with the surface energy of the support being larger than the surface energy of the coating solution. 2. The viscosity is 5 to 300 cp at a shear rate of 10 ⁴ sec ^-1
A method for producing an ink jet recording sheet, comprising applying a coating liquid. 3. The viscosity is 5 to 300 cp at a shear rate of 10 ⁴ sec ^-1
2. The method for producing an ink jet recording sheet according to the above 1, wherein the coating liquid is applied. 4. A method for producing an ink jet recording paper, comprising applying the coating solution at a pH of 3.0 to 7.0 (25 ° C.). 5. 4. The method for producing an ink jet recording sheet according to any one of the above items 1 to 3, wherein the coating is performed with the pH of the coating liquid being 3.0 to 7.0 (25 ° C.). 6. A method for producing an ink jet recording paper, wherein the coating is performed at a coating liquid temperature of 30 to 50C. 7. 6. The method for producing an ink jet recording sheet according to any one of the above items 1 to 5, wherein the coating is performed at a coating liquid temperature of 30 to 50C. 8. A method for producing an ink jet recording paper, comprising applying a coating liquid on a support having a surface roughness of 0.2 μm or less. 9. 8. The method for producing an ink jet recording sheet according to any one of the above items 1 to 7, wherein a coating liquid is applied on a support having a surface roughness of 0.2 μm or less. 10. A method for producing an ink jet recording paper, wherein the coating is performed in an environment having a cleanliness class of 1000 or less. 11. 10. The method for producing an ink jet recording sheet according to any one of the items 1 to 9, wherein the method is applied in an environment having a cleanness class of 1000 or less. 12. An ink jet recording paper manufactured by the manufacturing method of the above 1 to 11.

Hereinafter, the present invention will be described in detail. In order to obtain high image quality, it is necessary to increase the thickness of the ink jet recording layer in the ink jet recording paper, for example, to a dry film thickness of 30 μm or more, preferably 35 μm or more. In order to increase the film thickness in this way, it is naturally necessary to apply a thick coating solution on the support. In the case of coating with a thick film thickness, cracks tend to occur on the film surface after coating or in the process of drying after coating. In addition, because of the thickness, the uniformity of the film at the time of coating tends to deteriorate. A method for obtaining a uniform inkjet recording paper free of cracks even when coated with such a thick coating film thickness has not been disclosed so far, and various attempts have been made to apply the coating under known conditions. As a result, it was not possible to obtain ink jet recording paper having satisfactory performance such as cracks on the film surface of the ink jet recording layer and uniformity of the film.

[0008] In particular, these demands are great in ink jet recording papers of the type called a gap type among the ink jet recording papers. Satisfactory performance in which cracks on the film surface of the gap type ink jet recording layer and film uniformity are improved. It was difficult to obtain an inkjet recording paper having the following. We conducted various studies with the aim of suppressing cracking and obtaining a uniform coating film, and as a result, by selecting some application conditions, it was possible to reduce cracking and obtain a uniform coating film I understand. These are particularly effective when producing a gap type ink jet recording paper.

The void-type ink jet recording paper is usually composed mainly of paper or a synthetic resin laminated paper such as a thermoplastic resin film, synthetic paper, a paper support laminated on both sides with polyethylene, wood fiber or synthetic fiber. An ink-absorptive layer having voids is coated on a sheet-like substance such as a nonwoven fabric. In the ink-absorbing layer, solid fine particles having an average particle size of 500 nm or less, particularly 200 nm or less are dispersed in a water-soluble organic polymer compound in order to increase the porosity to enhance the ink absorbability and simultaneously satisfy the fixing property of the ink.・ It is contained.

[0010] In order to improve the image quality, these ink-absorbing layers are formed on these supports at a thickness of 30 µm or more, preferably 35 µm or more.
Coating is performed by various methods such as a dip coating method, a bar coating method, a blade coating method, an air knife method, a slide coating device, and a curtain coating method so as to have a dry film thickness of not less than μm and not more than 60 μm. In the method of the present invention, the viscosity of the coating liquid was measured at a shearing rate of 10 ⁴ sec ^-1 at the temperature of the coating in order to uniformly coat the ink absorbing layer coating on the support at the time of coating. Sometimes 5-300 cp,
It is important to apply using a coating solution that is preferably 10 to 150 cp.
It is necessary to apply as 0 to 70 mN / m (millinewton / meter), preferably 25 to 55 mN / m. Thereby, even in the case of a thick coating film, uniformity at the time of coating is increased, and stable coating can be performed. Further, the pH of the coating solution is 3.0 to 3.0.
7.0 (25 ° C.), and the coating liquid temperature is 30 to 50.
° C. It is preferable to apply, the viscosity, surface tension, etc., the concentration of each component including the polymer component in the coating solution, that the physical properties of the liquid can be adjusted without impairing practical ease of handling, Further, it is also suitable for the stability of the coating liquid components and for preventing the drying after coating from imposing too much load.
By setting the conditions so as to satisfy these conditions, uniform coating can be stably performed even in a thick film thickness.

However, in order to sufficiently prevent the film from cracking during the application of the coating film and during the drying process, it is important that the surface energy of the support is larger than the surface energy of the coating solution. I understood. By taking the surface energy of the support larger than the surface energy of the coating solution, the spreadability of the coating solution on the surface of the support is ensured, the coating is performed without cissing, and a uniform film surface is formed (that is, the coating is performed). The present inventors have found that this condition has a great effect on the generation of cracks in the drying process in which the components are gradually concentrated in the coating film after coating as well as during coating. Were found. These are particularly effective when the film thickness is thick as described above, and when these relationships are satisfied, cracks when concentrated are extremely reduced.

The surface energy of the support is usually 35 to 55.
mN / m (millinewton / meter), whereas the surface energy of the coating solution cannot be said unconditionally.
Less than the surface energy of the support and 30-50
It is preferably in the range of mN / m. The difference between the surface energies of the support and the coating liquid is preferably 2 mN / m or more, more preferably 5 mN / m or more, and this is important for obtaining the above effects. By maintaining these conditions, the dynamic surface tension of the coating solution is kept within a preferable range during coating, and uniform coating can be performed. In addition, after the coating is concentrated and dried, generation of cracks in the process of drying is sufficiently performed. Can be suppressed. Although the reason is not clear, it is considered that the adhesion between the support and the ink-absorbing layer at the concentrated stage and the balance of the tension in the layer are preferably maintained. On the other hand, when the value is smaller than this value, the stability of coating is lost and the number of cracks increases. The larger the difference in surface energy is, the better the effect is obtained. However, in practice, the upper limit of the difference between the support and the coating liquid is 30 mN / m. If the thickness is too large, the application unevenness becomes large when the coating is made thick, and it is difficult to obtain a uniform layer. In the above description, the surface energies of the support and the coating solution are values in a standard state (25 ° C.).
It can be measured by a plate method using a surface tension measuring device such as FIBRO DAT1100 manufactured by Company O.
Further, the surface energy of the support can be calculated by measuring the contact angle with water or iodomethane according to the Young's and Fowkes equations as described later.

Further, when the above range of the surface energy and the above relationship in the present invention are satisfied and the viscosity of the coating liquid is measured at the coating temperature at a shear rate of 10 ⁴ sec ⁻¹ , 5
By setting the thickness to 300 cp, it is possible to obtain an ink jet recording sheet in which the uniformity of the film thickness is higher and the occurrence of cracks is suppressed. When the viscosity is in this range, it seems to effectively work to prevent the occurrence of cracks when the coating film is dried. The viscosity value is a value measured using a rotational viscometer.
It can be measured using an F3 PG142 RV2 type viscometer manufactured by ke.

In particular, when the film thickness is large, it is highly effective to apply the coating under an environment of a cleanliness class of 1000 or less to avoid the generation of dust in producing a film without cracks. Since these foreign matters locally impair the uniformity of the film and cause the generation of cracks on the film surface, it is necessary to perform coating under an environment having a cleanness class of 1000 or less. It is preferable when applying. US Federal Standard 209B for cleanliness
Is a numerical value represented by the number of particles of 0.5 μm or more contained in one cubic ft, and can be measured by a usual particle counter. The environment herein means a zone including a coating machine and drying, and also includes a zone where coating and coating are concentrated and dried on a support.

The air gap type ink jet recording paper manufactured by the method of the present invention has a relatively uniform thickness of the ink absorbing layer and a small number of cracks despite having a relatively thick ink absorbing layer. Yes, it can be used as high-quality inkjet recording paper with high maximum density and no image unevenness. In the present invention, an ink jet recording paper which gives a uniform, crack-free and high image quality by applying a void type ink absorbing layer on a support under the above conditions is provided, but these ink absorbing layers are coated on the support. Any method such as a dip coating method, a bar coating method, a blade coating method, an air knife method, a slide coating method and a curtain coating method can be used. If necessary, these ink-absorbing layers are formed by applying these layers in sequence, such as applying a subbing layer and then applying. Both the application of the ink-absorbing layer and the undercoat layer can be similarly advantageously applied by the above-mentioned method.
However, of these, in particular, JP-B-49-24
No. 133, curtain coater as described in JP-A-6-183132, and U.S. Pat. No. 2,761,419.
No. 2,761,791 and 5,849,3
No. 63, No. 5,843, 530, No. 5,736,
It is preferable to carry out coating by a slide coater as described in JP-A No. 067 or the like in order to carry out coating in the present invention.
In addition, a concentrated solution can be used, and even if these are used, application by an extruder method which is excellent in productivity in that cracks are hardly generated is also preferable.

Here, the ink absorbing layer used in the present invention will be described in detail. The ink-absorbing layer is a layer in which solid fine particles are dispersed and contained in a water-soluble organic polymer compound in order to increase the porosity to enhance the ink-absorbing property and simultaneously satisfy the fixing property of the ink. Examples of solid fine particles used in these ink-absorbing layers include calcium carbonate, calcium sulfate, magnesium hydroxide, basic magnesium carbonate, alumina, aluminum hydroxide, synthetic silica, silicates such as calcium silicate, aluminum hydroxide, Examples include barium sulfate, titanium oxide, zinc carbonate, zinc oxide, silicon oxide, zeolite, and lithobon.

Examples of the water-soluble organic high molecular compound for preparing the ink absorbing layer by dispersing the solid fine particles include gelatin, polyvinylpyrrolidone, sodium polyacrylate, polyvinyl alcohol and modified products thereof.
Starch and its modified products, oxidized starch, etherified starch, cellulose derivatives such as vinyl acetate, carboxymethylcellulose, hydroxyethylcellulose, casein, soybean protein, silyl-modified polyvinyl alcohol, etc .; maleic anhydride resin, styrene / butadiene copolymer, methyl Conjugated diene copolymer latex such as methacrylate / butadiene copolymer; acrylic polymer latex such as acrylate and methacrylate polymer or copolymer; vinyl polymer latex such as ethylene / vinyl acetate copolymer Coated latex; or a functional group-modified polymer latex with a monomer containing a functional group such as a carboxyl group of these polymers; water-soluble organic polymers such as thermosetting synthetic resins such as melamine resin and urea resin (water-soluble polymer) ) Etc., and two or more Mixed use is also possible.

The solid fine particles used in the ink-absorbing layer may be those synthesized in the presence of a water-soluble organic polymer compound as described in, for example, JP-A-9-164761. In this case, the inorganic substance that can be used as a raw material for synthesizing the solid fine particles is not particularly limited, but aluminum sulfate, aluminum nitrate,
Aqueous solutions of aluminum salts such as aluminum chloride and the like, alkali metal aluminates such as sodium aluminate and potassium salt or both, water-soluble aluminum compounds, salts of silicon such as sodium silicate or aluminum isopropoxide It is preferable to use a metal alkoxide such as tetraethoxysilane.

The solid fine particles preferably have an average particle size of 500 nm or less, particularly 200 nm or less. The thickness of the ink absorbing layer depends on the type of ink used and its solvent,
Strictly determined by the amount of ink, etc.
m is preferred. If the amount is less than the above range, the absorbance is insufficient and the image is blurred.If the amount exceeds the above range, the absorptivity becomes too high and the dye is absorbed and carried, so that the image density may be reduced. Both are not preferred.

The ratio of the solid fine particles to the binder used is as follows:
If the amount of the binder is too large, the solid fine particles cannot sufficiently exhibit high-definition image quality. Therefore, it is appropriate to use the binder in an amount of about 0 to 50% by weight, more preferably 5 to 20% by weight, based on the total amount of the solid fine particles. In the present invention, as other additives that can be added to the ink absorbing layer, a dispersant of solid fine particles,
Hardeners, thickeners, flow improvers, defoamers, defoamers, release agents, foaming agents, penetrants, coloring dyes, coloring pigments, fluorescent brighteners, ultraviolet absorbers, antioxidants, Preservatives, antibacterial agents, waterproofing agents, wet paper strength agents, dry paper strength agents, and the like can also be appropriately compounded.

In the ink jet recording sheet of the present invention, the ink-absorbing layer is not necessarily required to be composed of one layer, but may be composed of a plurality of layers. Examples of the support used in the present invention include paper, thermoplastic resin film, synthetic paper, synthetic resin laminated paper such as a paper support laminated on both sides with polyethylene, and nonwoven fabric mainly composed of wood fibers and synthetic fibers. Sheet materials are preferred. In the case of paper, sizing agents such as neutral sizing agents, polymer sizing agents, acidic sizing agents, etc. can be used alone or in combination with or without an internal sizing agent. But there is no restriction. Conventionally known pigments are used as an internal filler and a white pigment for a paper support, and a single region can be used in combination. Examples thereof include light calcium carbonate, heavy calcium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, and dioxide. White inorganic pigments such as titanium, zinc oxide, zinc sulfide, zinc carbonate, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic silica, aluminum hydroxide, alumina, lithopone, zeolite, magnesium carbonate, magnesium hydroxide, and styrene Organic pigments, such as organic plastic pigments, acrylic plastic pigments, polyethylene, microcapsules, urea resins, and melamine resins. Furthermore, when the support is paper, it contains a neutral sizing agent and filler, the wood pulp / filler ratio is 90-70% by weight / 10-30% by weight, and the weight is 60-120 g / m ^2. However, there is no limitation.

These supports have a surface roughness of 0.2 μm.
The following is preferred. When the ink absorbing layer is applied thickly as in the present invention, the surface roughness in this range is effective for cracking during drying and uniformity of application.
If the surface roughness exceeds this value, cracks increase and the applicability is impaired. In order to impart such surface roughness to the surface of the support, there is a method of performing heat treatment using a roller or a block having a rough surface, so-called calendering, or a method of including organic / inorganic fine particles in the support surface layer. A synthetic resin-laminated paper such as a paper support obtained by laminating paper having the above-mentioned pigment with polyethylene on both sides has a preferable rough surface.

These supports may be subjected to a surface treatment such as a corona discharge treatment or a plasma discharge treatment, or may be provided with an undercoat layer, to improve the adhesion between the support and the ink absorbing layer, and to shrink the ink absorbing layer during drying. Its purpose is stress relaxation. When an undercoat layer is provided, the coating amount is usually 0.01 g / m ^{2 to} 0.1 g / m ² .
It is 4 g / m ² , but is not limited to this as long as it has an effect as an undercoat layer. Examples of the compound used for the undercoating of the present invention include hydrophilic polymer compounds having low solubility in water, but are not limited thereto.

[0024]

EXAMPLES The present invention will be described below in more detail with reference to examples, but embodiments of the present invention are not limited thereto. Example 1 The average particle diameter of the primary particles dispersed uniformly in advance is about 0.5.
012 μm fumed silica (manufactured by Nippon Aerosil Co., Ltd .:
A200) of 450 liters of a 20% aqueous solution A1 (pH = 2.3, containing 1% by weight of ethanol) was added to an aqueous solution C1 containing 14% by weight of a cationic polymer, 5% by weight of n-propanol, and 2% by weight of ethanol (pH: 2.3). = 2.5,
The mixture was added to 110 liters of an antifoaming agent SN381 manufactured by Sannobuco (containing 2 g) while stirring at room temperature.

Then, the mixture was dispersed at a pressure of 500 kg / cm ² with a high-pressure homogenizer manufactured by Sanwa Kogyo Co., Ltd.
Finished to 30 liters, almost transparent silica dispersion B1
I got This dispersion was filtered using a TCP-30 type filter manufactured by Advantech Toyo Co., Ltd. having a filtration accuracy of 30 μm.

Next, the following additives were successively mixed using the above dispersion to prepare a coating liquid (CS1) (the amount of the liquid prepared was adjusted to 1 liter). Silica dispersion B1 580 ml Polyvinyl alcohol (PVA235 manufactured by Kuraray) 5% aqueous solution 250 ml Silicon dispersion (BY-22-839 manufactured by Dow Corning Silicone Toray) 30 ml Latex dispersion (AE803 manufactured by Showa Kogaku Kogyo) 20 ml 8.5 ml of ethanol Pure water (to make the total amount 1000 ml) The pH of CS1 of the obtained coating composition was 4.2 at 40 ° C.

Next, each coating solution was filtered three times with a 25 μm filter, and then wet coated with a 200 μm thick film on a 240 μm thick paper support coated on both sides with polyethylene.
m. At that time, the surface energy of the support and the surface roughness of the support were changed to the values shown in Table 2 according to the method shown below, and the physical properties of the coating solution and the coating conditions were also shown in Table 2. Changed as shown. Samples 1 to 16 after drying and Comparative Samples 1 to 5 were obtained.
The dry film thickness was 37 μm. <Surface Roughness of Support> The surface roughness of the support was changed by successively calendering (so-called molding) with heating rolls having different rough surfaces. Measurement is made by Mitutoyo CS4
11 Measured by CS-1. <Coating solution viscosity> Ethanol was added to the coating solution at a maximum of 3%, and the solid content concentration was changed to change as shown in Table 2, and a rotational viscometer F3 PG142R manufactured by Haake was used.
The measurement was performed at each application temperature according to V2. <Surface energy> The coating liquid was changed by appropriately adding the amount of a fluorine-based surfactant F144D (manufactured by Dainippon Ink). The measurement is performed by the plate method,
BRO DAT1100 (manufactured by FIBRO) was used.

As for the support, a gelatin undercoat layer is provided in a thickness of 0.1 μm, and a fluorine-based surfactant F144D (manufactured by Dainippon Ink) is appropriately added to the undercoat layer coating solution similarly to the ink absorbing layer coating solution. It was adjusted by that. The surface energy of the support is determined based on the solid and liquid droplets.
Using the relationship between the contact angle of d) and each component of the surface energy, the water (polar solvent) and iodomethane (non-polar solvent)
From the contact angles of the different types of droplets,
ung and Fowkes can be calculated.

[0029]

(Equation 1)

The surface tension, non-polar components and polar components of water and iodomethane are as shown in Table 1 below.

[0031]

[Table 1]

The surface energy of the support is determined by the contact angle between the support surface and water or iodomethane,
Was substituted into the above equation to calculate each value of the surface energy of the support. In the above equation, γ _S , γ _L , γ _SL and θ are as shown in FIG. Also, gamma _S is the surface energy of the substrate ^{_{(= γ S d + γ S}} p), the gamma _S ^d and gamma _S ^p is a non-polar component of the surface energy of each substrate (d) and polar component (p). <Cleanliness> Regarding cleanliness, US Federal Standard 2
The number of particles of 0.5 μm or more contained in 1 cubic ft of air was expressed by 09B, and the booth provided with the coater and the dryer was changed in position by a particle counter and measured at five points, and the average was taken.

The obtained sample was evaluated. For cracks, count the number generated in 1 m ² of the coated sample. For coatability, apply the following criteria for smearing, spot failure, streak failure, and end coatability as shown below. did. ◎: Smooth and good ○: Smooth and almost good, but slight unevenness at the edge △: Slight unevenness over the entire surface, some point-like failure, slight unevenness at the end ×: Unevenness over the entire surface , Repelling has also occurred. Table 2 shows the evaluation results with streak failures, many point-like failures, and large edge disturbances.

[0034]

[Table 2]

Example 2 Alumina hydrate was used as a pigment. The specific surface area and the pore volume are 200.2 m ^{2 /} g and 0.71 ml / g, respectively.
Met. The specific surface area is the BET specific surface area,
Calculated using the method of r et al. The pore volume was measured using a nitrogen adsorption / desorption method after deaeration at 120 ° C. for 24 hours (Autosoap I, manufactured by Kantachrome).

The production method is described in US Pat. No. 4,242,27.
An aluminum alkoxide is produced by the method described in No. 1. Next, the aluminum alkoxide was hydrolyzed by the method described in U.S. Pat. No. 4,202,870 to produce an alumina slurry. Water was added to the alumina slurry until the alumina hydrate solid content became 7.9%. The pH of the alumina slurry was 9.5. 3.
The pH was adjusted to 6.8 by adding a 9% nitric acid solution. This was aged at 110 ° C. for 6 hours to obtain a colloidal sol. Alumina hydrate obtained by spray drying this colloidal sol at 75 ° C. was used.

After dispersing the alumina hydrate in ion-exchanged water, polyvinyl alcohol (Kuraray PVA23) was used.
An aqueous solution of ion-exchanged water in which 5) was dissolved was added. At this time, the solid content weight of alumina hydrate / the solid content amount of polyvinyl alcohol (pigment / binder = P / B) was 13 /
Then, the mixture was measured, added, mixed and stirred, and subjected to a dispersion treatment to obtain a coating liquid. Next, after the obtained coating solution was filtered three times with a 25 μm filter, a paper support (thickness: 240) having the same surface energy and surface roughness as in Example 1 was changed.
The coating liquid properties and coating conditions were changed in the same manner as in Example 1 to obtain a wet film thickness of 250 μm, followed by drying. Samples 17 to 32 and Comparative Samples 6 to 10 were obtained. The state of the film surface of the obtained sample was evaluated in the same manner as in Example 1 for cracks. The dry film thickness was 4
It was set to 0 μm. Table 3 shows the results.

[0038]

[Table 3]

The same results as in Example 1 were obtained even when alumina was used as the pigment instead of the void type ink absorbing layer.

[0040]

According to the method for producing an ink jet recording sheet of the present invention, a uniform coated and dried surface free from cracks and unevenness can be formed, and an ink jet recording sheet having a high quality air gap type recording layer can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a contact angle between a substrate and a liquid and a component of surface energy.

[Explanation of symbols]

surface energy component θ contact angle of the surface energy component gamma _SL base direction of the surface energy component gamma _L solution the tangential direction of the gamma _S base direction

Claims (12)

[Claims] 1. A method for producing an ink jet recording paper, wherein the coating is performed with the surface energy of the support being larger than the surface energy of the coating solution. 2. The viscosity is 5 to 5 at a shear rate of 10 ⁴ sec ^-1 .
A method for producing an ink jet recording paper, comprising applying a coating liquid of 300 cp. 3. The viscosity is 5 to 5 at a shear rate of 10 ⁴ sec ^-1 .
2. The method according to claim 1, wherein a coating liquid of 300 cp is applied. 4. The coating solution has a pH of 3.0 to 7.0 (25 ° C.).
A method for producing an ink jet recording paper, characterized in that the method is applied as follows. 5. A coating solution having a pH of 3.0 to 7.0 (25 ° C.).
The method for producing an ink jet recording sheet according to any one of claims 1 to 3, wherein the ink is applied as a coating. 6. A method for producing an ink jet recording paper, wherein the coating is performed at a coating liquid temperature of 30 to 50 ° C. 7. The method for producing an ink jet recording sheet according to claim 1, wherein the coating is performed at a coating liquid temperature of 30 to 50 ° C. 8. A method for producing an ink jet recording paper, comprising applying a coating liquid on a support having a surface roughness of 0.2 μm or less. 9. The method according to claim 1, wherein a coating liquid is applied on a support having a surface roughness of 0.2 μm or less. 10. A method for producing ink jet recording paper, wherein the method is applied in an environment having a cleanness class of 1000 or less. 11. The method according to claim 1, wherein the application is performed in an environment having a cleanness class of 1000 or less. 12. An ink jet recording paper manufactured by the manufacturing method according to claim 1. Description: