JP4528675B2 - Manufacturing method of image recording medium - Google Patents

Description

  The present invention relates to a method for manufacturing a high-quality image recording medium, and more particularly to a method for manufacturing an image recording medium in which a long roll body is cut into a curl-free sheet body in the manufacturing process of the image recording medium.

  In recent years, with the rapid development of the information industry, various information processing systems have been developed, and recording methods and apparatuses suitable for the information processing systems have been developed and put into practical use.

  Examples of recording methods that have been put to practical use include electrophotographic methods, ink jet recording methods, thermal recording methods, sublimation transfer methods, thermal transfer methods and the like in addition to silver salt photography. In any of the recording methods, it is required to obtain a high-quality image with sharp images and vivid colors.

  Among the recording methods, for example, the inkjet recording method is capable of recording on various types of recording materials, the hardware (device) is relatively inexpensive, compact, excellent in quietness, and the like. Of course, it is also widely used in so-called home use. In recent years, various types of ink-jet recording media have been developed as the resolution of ink-jet printers and the development of hardware (devices) have increased. In recent years, it has become possible to obtain so-called photographic-like high-quality recorded matter. .

  By the way, an ink jet recording medium is manufactured by applying an ink receiving layer to a support, drying it, and winding it on a long roll. Here, the semi-finished long roll is generally a jumbo roll having a width of about 0.5 to 2.5 m and a length of about 500 to 5000 m. Finished. A problem in this manufacturing process is that curling curls occur when stored in a jumbo roll state. In particular, when a jumbo roll is processed into a sheet-like product, the curl of the jumbo roll may become the curl of the sheet-like product as it is. This problem becomes prominent particularly when the support is relatively high in rigidity. When curling a sheet-like product, troubles such as poor transportability and meandering occur during printing, and when printing without a border, the product may damage the print head due to end curl.

  As a countermeasure against curling that occurs as described above, methods for improving the backing layer have been proposed (see, for example, Patent Documents 1 to 3). Further, a method for improving the support has been proposed (see, for example, Patent Document 4). Furthermore, a method of humidifying or heating has been proposed (see, for example, Patent Document 5). However, it was insufficient as a countermeasure against curl curls.

On the other hand, a processing method for decurling a long roll-shaped recording material in which the ink image receiving layer surface is wound inward has been proposed, but the problem of cracking in the ink image receiving layer surface has not been completely solved. (For example, see Patent Document 6).
Japanese Patent Laid-Open No. 5-28622 JP-A-8-310111 Japanese Patent Laid-Open No. 11-291616 JP 2000-85243 A JP-A-8-269900 JP 2000-356051 A

  Accordingly, an object of the present invention is to solve the above problems. That is, the present invention eliminates curl curl when cutting a long roll-shaped image recording medium into a sheet-like product, and at the same time suppresses the occurrence of cracks in the recording layer. An object of the present invention is to provide an image recording medium manufacturing method with improved defects.

Means for solving the above-mentioned problems are as follows. That is, the present invention
<1> A sheet-like material having a recording layer on one thermoplastic resin layer of a support provided with a thermoplastic resin layer on both sides of a paper substrate, so that the surface having the recording layer faces outside. The long roll body web obtained by being unwound from the long roll body wound around the web is sent to the cutting mechanism, and the correction member is pressed against the web side of the long roll body having the recording layer. A method for producing an image recording medium for cutting while correcting curl, wherein the thermoplastic resin layer is formed by melt extrusion, and the recording layer has a thickness A corresponding to the thickness A of the thermoplastic resin layer having the recording layer. The ratio (B / A) of the thickness B of the thermoplastic resin layer on the side opposite to the side having the recording layer is 0.9 to 1.5, and the thickness C of the recording layer and the heat on the side having the recording layer are The recording layer with respect to the sum of the thickness A of the plastic resin layer The ratio (B / (A + C)) of the thickness B of the thermoplastic resin layer on the side opposite to the side having the thickness is 0.4 to 0.8, and the correction member is a roller having a diameter of 8 to 16 mm. The roll of the roll of the rolled long roll body is made while the curling of the straight member and the web of the rolled long roll body is held so that the angle is less than 60 °. A method of manufacturing an image recording medium, which is performed by conveying a body.

<2> The method for producing an image recording medium according to <1>, wherein the holding angle is 45 ° or more and less than 55 ° .

<3> The method for producing an image recording medium according to <1> or <2>, wherein the thickness A of the thermoplastic resin layer having the recording layer is 15 to 60 μm.
<4> The method for producing an image recording medium according to any one of <1> to <3>, wherein the paper substrate contains 25% by mass or more of kraft pulp made of acacia.

<5> The method for producing an image recording medium according to any one of <1> to <4>, wherein the recording layer is an ink receiving layer, and the image recording medium is an inkjet recording medium. is there.
<6> The method for producing an image recording medium according to <5>, wherein the ink receiving layer contains a water-soluble resin, a crosslinking agent capable of crosslinking the water-soluble resin, fine particles, and a mordant.

<7> The water-soluble resin is at least one selected from the group consisting of a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, a resin having a carbamoyl group, a resin having a carboxyl group, and gelatins. the fine particles of silica fine particles, colloidal silica, alumina fine particles, a method for manufacturing an image recording medium according to you wherein <6> is at least one selected from the group consisting of pseudo-boehmite.

<8> The ink receiving layer is a layer obtained by crosslinking and curing a coating layer coated with a coating solution containing at least fine particles and a water-soluble resin, and the crosslinking curing is performed by the coating solution and / or the following basic solution. And (1) at the same time when the coating solution is applied to form a coating layer, or (2) during the drying of the coating layer formed by coating the coating solution. Any one of <5> to <7>, which is performed by applying a basic solution having a pH of 7.1 or higher to the coating layer at any time before the layer exhibits reduced-rate drying. A method for producing an image recording medium according to one of the above.

  According to the present invention, when a long roll image recording medium is cut into a sheet product, curling curl is eliminated, and at the same time, the occurrence of cracks in the recording layer is suppressed, thereby conveying the printer due to curling. An image recording medium manufacturing method with improved defects can be provided.

In the method for producing an image recording medium of the present invention, a sheet-like material having a recording layer on one thermoplastic resin layer of a support having a thermoplastic resin layer provided on both sides of a paper substrate is obtained by using the recording layer. The web of the long roll body obtained by being unwound from the long roll body wound so that the surface having the outer side is fed out to the cutting mechanism, and the recording layer of the web of the long roll body A method of manufacturing an image recording medium in which a correction member is pressed to a side having a cut and cut while correcting a curl, wherein the thermoplastic resin layer is formed by melt extrusion, and the thermoplastic resin layer on the side having the recording layer is formed. The ratio (B / A) of the thickness B of the thermoplastic resin layer on the side opposite to the side having the recording layer to the thickness A is 0.9 to 1.5, and the thickness C of the recording layer is The thickness of the thermoplastic resin layer on the side having the recording layer To the sum of the thickness ratio of the B recording layer opposite to the thermoplastic resin layer and the side having the (B / (A + C) ) is 0.4 to 0.8, and wherein the straightening member is It is a roller having a diameter of 8 to 16 mm, and the curling of the web of the unrolled long roll body is carried out so that the angle between the straightening member and the unrolled long roll body web is less than 60 °. It carries out by conveying a long roll body, making it contact | abut to.

A method for producing an image recording medium of the present invention will be described with reference to FIG. FIG. 1 is an enlarged side view of an image recording medium manufacturing apparatus for carrying out the image recording medium manufacturing method of the present invention.
As shown in FIG. 1, the image recording medium manufacturing apparatus 12 includes a long sheet body supply mechanism 40 in which a long roll body 18a in which a sheet-like material is wound up in a roll shape is disposed, and the long sheet body supply. A transport mechanism 44 for feeding the web 18 of the long roll body obtained by unwinding the long roll body 18 a from the mechanism 40 to the cutting mechanism 42, and between the long sheet body supply mechanism 40 and the cutting mechanism 42. The straightening mechanism 46 that is disposed and corrects the curl of the web 18 of the long roll body and the web 18 of the long roll body that is disposed and cut on the downstream side of the cutting mechanism 42 are not collected as an image recording medium. It includes an alignment switching mechanism (not shown) that can be transferred to the alignment station and the disposal unit 50 shown in the figure. Further, the long sheet body supply mechanism 40 includes an unwinding terminal portion of the long roll body 18a and a unwinding tip end portion of the long roll body 18a newly disposed in the long sheet body supply mechanism 40. A joining portion 56 for joining is provided.

  The transport mechanism 44 includes a plurality of rewind rollers 58, a feed roller 60, a nip roller 62 that is slidably contactable with the feed roller 60, and a nip roller pair 64 that is close to the cutting mechanism 42. The feed roller 60 is rotatable in the direction of arrow A via a drive source (not shown), and the nip roller 62 is supported by a cylinder (not shown) or the like and can be raised and lowered.

  As shown in FIG. 1, a slitter 74 is disposed close to the upstream side of the feed roller 60. The slitter 74 includes a pair of slitter upper blades 76a and a slitter lower blade 76b disposed at both ends in the width direction of the web 18 of the long roll body, and the slitter upper blade 76a and the slitter lower blade 76b. An ear cutter 78 for cutting the cut ear is disposed below the slitter 74.

As shown in FIG. 1, the correction mechanism 46 includes a decurler rubber (correction member) 80 that is pressed against the web 18 of the long roll body, and the decurler rubber 80 between the two rewind rollers 58. And a control unit 79 that presses the web 18 from the surface having the recording layer.
Further, the cutting mechanism 42 includes a fixed blade 86a that extends in a direction intersecting the conveyance direction of the web 18 of the long roll body, and a movable blade 86b that can be moved up and down above the fixed blade 86a. With.

  In the image recording medium manufacturing apparatus 12, by rotating the feed roller 60 in the direction of arrow A, the long roll body 18 a is unwound, and the web 18 of the unrolled long roll body is curled by the correction mechanism 46. to correct. Further, the web 18 of the long roll body whose curl has been corrected is sent to the cutting mechanism 42 through the transport mechanism 44, where it is cut and distributed to an alignment station (not shown) or a disposal unit 50. The cut long roll web 18 distributed to the aligning station is aligned and then sent to an unillustrated stacking mechanism to obtain an image recording medium.

In the method for manufacturing an image recording medium of the present invention, the long roll body 18a has a recording layer of the web 18 of the long roll body in which the surface having the recording layer is wound around the outer winding and unwound by the correction mechanism 46. The decurler 80 which is a roller having a diameter of 8 to 16 mm is brought into contact with the side so that the holding angle between the web 18 of the long roll body and the decurler 80 is less than 60 °.
As described above, the decurler rubber 80 is made into a roller having a diameter of 8 to 16 mm, and the web 18 of the long roll body and the decurler rubber 80 are brought into contact with each other so that the holding angle is less than 60 °. It is possible to eliminate wrinkle curling and at the same time suppress the occurrence of cracks in the image receiving layer.
In addition, as a roller having a diameter of 8 to 16 mm used as the decurler rubber 80, a so-called free roller that can rotate without being driven is preferable from the viewpoint of suppressing the occurrence of scratches on the image receiving layer.

  Here, the holding angle will be described with reference to FIG. FIG. 2 is a schematic diagram for explaining the holding angle. As shown in FIG. 2, the hugging angle refers to an angle θ formed by a straight line connecting the center portion of the decurler rubber 80 and both end portions of the surface in contact with the long roll body 18 around which the decurler rubber 80 is wound, The maximum is 0 ° (when the unrolled long roll body 18 and the decurler rubber 80 contact at one point).

  The holding angle in the present invention must be less than 60 °, preferably 30 ° or more and less than 60 °, and more preferably 45 ° or more and less than 55 °. By setting the holding angle to less than 60 °, curling curl of the web 18 of the long roll body can be eliminated. On the other hand, if the holding angle is 60 ° or more, the resulting image recording medium is cracked.

  Moreover, in this invention, it is essential that the diameter of the roll-shaped decurler rubber 80 (correction member) is 8-16 mm, and it is preferable that it is 10-14 mm. If the diameter of the decurler rubber 80 is less than 8 mm, the recording layer is cracked and the glossiness is also lowered. Further, the ink is incurred on the side having the recording layer, and the transportability of the printer is deteriorated. On the other hand, if the diameter of the decurler rubber 80 exceeds 16 mm, curl curl will occur.

  Furthermore, in the present invention, the conveyance tension of the web 18 of the long roll body by being pressed against the decurler rubber 80 between the two rewinding rollers 58 is preferably 5 to 100 kg / m. m is more preferable, and 25 to 60 kg / m is still more preferable. When the transport tension is 5 to 100 kg / m, the recording layer is not cracked and incurs on the surface side having the recording layer, so that the transportability of the printer is not deteriorated. .

  On the other hand, the preferable conditions for correcting the curl are 20 to 28 ° C., and more preferably 23 to 25 ° C. Further, the humidity is 45 to 65% RH, and more preferably 50 to 60% RH. When the humidity is 20 to 28%, a desired size can be easily obtained without deteriorating dimensional stability.

Next, the sheet-like material will be described.
In the present invention, the sheet-like material that becomes an image recording medium by being wound and cut is formed on one of the thermoplastic resin layers of the support provided with the thermoplastic resin layers on both sides of the paper substrate. It has a recording layer.
Hereinafter, the sheet-like material in the present invention will be described in detail.

In the present invention, the thermoplastic resin layer is formed by melt extrusion, and the thermoplastic resin layer on the side opposite to the recording layer has a thickness A of the thermoplastic resin layer on the side having the recording layer. The ratio (B / A) of the thickness B is 0.9 to 1.5, and the sum of the thickness C of the recording layer and the thickness A of the thermoplastic resin layer on the side having the recording layer, the side having the recording layer thickness ratio B of the opposite side of the thermoplastic resin layer (B / (a + C) ) is Ru der 0.4-0.8.

  The (B / A) is more preferably 1.1 to 1.3 in terms of incurling with respect to the recording layer surface suitable for printer transportability. If (B / A) is 0.9 to 1.5, there will be no outcurling with respect to the recording layer surface, and incurling with respect to the recording layer surface will not be too strong. There is no.

  Further, (B / (A + C)) is more preferably 0.45 to 0.55 in terms of incurling with respect to the recording layer surface suitable for printer transportability. When (B / (A + C)) is 0.4 to 0.8, there is no outcurling with respect to the recording layer surface, and the incurling with respect to the recording layer surface is not too strong. There is nothing to do.

  In the present invention, the thickness A of the thermoplastic resin layer having the recording layer is preferably 15 to 60 μm, and more preferably 25 to 35 μm. When the thickness A of the thermoplastic resin layer is 15 to 60 μm, it is affected by the surface roughness of the paper substrate, so that the glossiness is not lowered and the entire thickness is prevented from increasing. There is no need to reduce the thickness of the substrate, and no reduction in stiffness occurs.

On the other hand, when the obtained image recording medium is used as an ink jet recording medium, the thickness of the recording layer (ink receiving layer) preferably has an absorption capacity sufficient to absorb all of the droplets. It is preferable to determine in relation to For example, when the ink amount is 8 nL / mm ² and the porosity is 60%, the thickness of the recording layer is preferably 15 μm or more, and more preferably 15 to 50 μm.

<Support>
(Paper substrate)
The base paper (paper substrate) used for the support according to the present invention is characterized by containing kraft pulp made of acacia. It is most preferable that the base paper contains 100% of kraft pulp made of acacia, but the base paper may contain pulp other than kraft pulp made of acacia, and the pulp other than kraft pulp made of acacia is softwood. Natural pulp selected from broad-leaved trees, etc., for example, pulp made of aspen, maple, poplar, birch, alder, oak, eucalyptus, pine, hemlock and the like is preferable. Among the above, aspen and maple are particularly preferable.

  In the base paper, 25% by mass or more of the constituent pulp is preferably made of kraft pulp made of acacia, and more preferably 50% by weight or more is made of kraft pulp made of acacia. When the blending amount of kraft pulp composed of acacia in the constituting pulp is 25% by mass or more, the smoothness of the support is improved and the glossiness is further improved.

  The method for producing kraft pulp made of acacia according to the present invention is not particularly limited, and a general method for producing kraft pulp can be widely used. One specific method is shown below.

  Kraft pulp made of acacia is beaten so that the water retention is 150 to 180%. Here, the degree of water retention refers to sucking and filtering the beaten pulp suspension in a suitable filtration cup called a centrifugal cup, and then putting each container into a settling tube of a centrifuge and centrifuging for a certain period of time under certain conditions. Then, the dehydrated pulp is taken out, weighed, and then dried at 105 ° C. to obtain the absolute dry mass. The mass after centrifugation is A ′, and the mass after the absolute dry is B ′. It is represented by Equation 1.

  In the present invention, it is preferable that the kraft pulp made of acacia is beaten with a declarifier or the like so that the water retention obtained from the formula 1 is 150 to 180%. On the other hand, pulp other than kraft pulp made of acacia is separately prepared, and this pulp is mixed with the kraft pulp made of acacia. When the water retention of kraft pulp made of acacia is in the range of 150 to 180%, the pulp fiber is sufficiently softened and smoothness is improved. Dehydration failure on the paper machine wire and the amount of dry steam used There will be no increase.

  The above-mentioned mixed pulp has sizes such as clay, talc, calcium carbonate, urea resin fine particles, rosin, alkyl ketene dimer, higher fatty acid, epoxidized fatty acid amide, paraffin wax, alkenyl succinic acid, etc., if necessary. Agents, starch, polyamide polyamine epichlorohydrin, paper strength enhancing agents such as polyacrylamide, fixing agents such as sulfate bands and cationic polymers may be added.

  Paper making the prepared pulp slurry. In this paper making process, the web side corresponding to the coated surface on which the recording layer of the base paper is coated is dried by pressing the dryer canvas against the drum dryer cylinder. In this process, the tensile force of the dryer canvas is 1 Adjust to the range of 5-3 kg / cm and dry.

  On the surface (one side or both sides) of the base paper dried as described above, polyvinyl alcohol or a modified product thereof and / or fluorescent whitening agent such as starch, diaminostilbene disulfonic acid, calcium chloride, magnesium chloride, aluminum chloride A polyvalent metal chloride such as can be applied.

Is not particularly limited thickness of the material substrate, the basis weight is desirably ^{50~250g / m 2, 100~200g / m} 2 is more preferable. In addition, since smoothness is desired for the obtained image recording medium as an inkjet recording medium, it is desirable that the surface of the support is also excellent in smoothness and flatness. For this purpose, a machine calendar, a super calendar, a soft calendar, etc. are used. It is preferable to use the surface treatment by applying heat of 50 to 250 ° C. and pressure of 50 to 300 kg / cm.

(Thermoplastic resin layer)
The thermoplastic resin used in the thermoplastic resin layer may be a styrene-butadiene latex, an acrylic latex, or an acrylic silicone latex, but is preferably a polyolefin resin. For example, an α-olefin homopolymer such as polyethylene and polypropylene, a mixture of these various polymers, or a random copolymer of ethylene and vinyl alcohol is preferred.
As the polyethylene, for example, LDPE (low density polyethylene), HDPE (high density polyethylene), and L-LDPE (linear low density polyethylene) can be used alone or in combination.
In the case of polyethylene, the melt flow rate before processing is a value measured according to JIS 7201 (Condition 4 in Table 1), and preferably 1.2 to 12 g / 10 min.

Methods for forming the thermoplastic resin layer on the paper substrate include melt extrusion, wet lamination, and dry lamination, with melt extrusion being most preferred. When the thermoplastic resin layer is formed by the melt extrusion, the substrate is pretreated before the thermoplastic resin layer is melt extruded to the substrate in order to strengthen the adhesion between the substrate and the thermoplastic resin layer. It is preferable.
Pretreatment of the substrate includes acid etching treatment using a mixed solution of chromic sulfate, flame treatment using a gas flame, ultraviolet irradiation treatment, corona discharge treatment, glow discharge treatment, anchor coat treatment such as alkyl titanate, and the like, which can be freely selected. In particular, corona treatment is preferable from the viewpoint of simplicity. In the case of corona treatment, it is necessary to treat so that the contact angle with water is 70 ° or less.

  Known examples of the anchor coating agent include organic titanium, isocyanate (urethane) polyethyleneimine, polybutadiene, and the like. Specifically, as the organic titanium system, alkyl titanates such as tetraisopropyl titanate, tetrabutyl titanate and tetrastearyl titanate, titanium acylates such as butoxytitanium stearate, titanium chelates such as titanium acetylacetonate, etc. are known. Yes. Further, as the isocyanate type (urethane type), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HMDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI) and the like are known.

The application of the image recording medium obtained in the present invention is not particularly limited, and can be suitably used for various applications that require high-quality images with high brightness, depth, clarity, and sharpness. In addition to inkjet recording media described later, it is also suitable as a support material for thermal transfer image receiving recording media, sublimation transfer image receiving recording media, electrophotographic image receiving recording media, thermosensitive color recording media, silver salt photographic photosensitive media, printing paper, and the like. is there.
Hereinafter, preferred embodiments of the sheet-like material when the image recording medium obtained by the present invention is used as an ink jet recording medium will be described.

  The sheet-like material in the present invention has a recording layer on the thermoplastic resin layer, and when the obtained image recording medium is used as an inkjet recording medium, it has an ink receiving layer as the recording layer.

[Ink receiving layer]
The ink receiving layer when used as the ink jet recording medium preferably contains at least a water-soluble resin, a cross-linking agent capable of cross-linking the water-soluble resin, fine particles, and a mordant. The component of this can be contained.

  The ink receiving layer is constituted to have a porous structure by containing fine particles, thereby improving the ink absorption performance. In particular, when the solid content of the fine particle ink receiving layer is 50% by mass or more, and more preferably more than 60% by mass, it is possible to obtain a more favorable porous structure, thereby further improving the ink absorbability. be able to. Here, the solid content of the fine particle ink receiving layer is a content calculated based on components other than water in the composition constituting the ink receiving layer.

  The porous ink-receiving layer is a layer having a porosity of 50 to 75%, preferably 60 to 70%. If the porosity is 50% or less, ink absorbability may be insufficient, and if it is 75% or more, a problem of powder falling due to insufficient binder may occur. Further, in view of the quality of the ink jet recording medium, the thickness of the ink receiving layer is preferably 20 to 40 μm, and the 60 ° gloss is preferably 30 to 70%.

-Fine particles-
As the fine particles, either organic fine particles or inorganic fine particles can be used. Preferred examples of the organic fine particles include polymer fine particles obtained by, for example, emulsion polymerization, microemulsion polymerization, soap-free polymerization, seed polymerization, dispersion polymerization, suspension polymerization, and the like. Specifically, polyethylene, polypropylene, Examples include polystyrene, polyacrylate, polyamide, silicon resin, phenol resin, natural polymer powder, latex or emulsion polymer fine particles, and the like.

Examples of the inorganic fine particles include silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, pseudoboehmite, zinc oxide, Examples thereof include zinc hydroxide, alumina, aluminum silicate, calcium silicate, magnesium silicate, zirconium oxide, zirconium hydroxide, cerium oxide, lanthanum oxide, and yttrium oxide.
Among these, inorganic fine particles are preferable from the viewpoint of ink absorbability and image stability, and silica fine particles, colloidal silica, alumina fine particles, or pseudoboehmite are preferable from the viewpoint of forming a better porous structure. The fine particles may be used as primary particles or in a state where secondary particles are formed. The average primary particle size of these fine particles is preferably 2 μm or less, and more preferably 200 nm or less.

  Among these, silica fine particles are generally roughly classified into wet method particles and dry method (vapor phase method) particles according to the production method. In the wet method, a method is mainly used in which active silica is produced by acid decomposition of silicate, and this is appropriately polymerized and coagulated and precipitated to obtain hydrous silica. On the other hand, the gas phase method is a method by high-temperature gas phase hydrolysis of silicon halide (flame hydrolysis method), a method in which silica sand and coke are heated and reduced by an arc in an electric furnace and oxidized with air. The method of obtaining anhydrous silica by the (arc method) is the mainstream, and the “gas phase method silica” means anhydrous silica fine particles obtained by the gas phase method. As the silica fine particles in the present invention, gas phase method silica fine particles are particularly preferable.

Vapor phase silica is different from hydrous silica in terms of the density of silanol groups on the surface, the presence or absence of vacancies, etc., and exhibits different properties, but is suitable for forming a three-dimensional structure with a high porosity. The reason for this is not clear, but in the case of hydrous silica, the density of silanol groups on the fine particle surface is high at 5 to 8 / nm ² , and the silica fine particles tend to aggregate (aggregate) easily. In the case of the method silica, the density of silanol groups on the surface of the fine particles is 2 to 3 / nm ² , so that it is sparse soft agglomeration (flocculate), resulting in a structure with a high porosity. Is done.

  Since the vapor phase silica has a particularly large specific surface area, the ink absorption and retention efficiency is high, and since the refractive index is low, transparency can be imparted to the receiving layer by dispersing it to an appropriate particle size. It is characterized by high color density and good color development. The transparency of the receiving layer is important not only for applications that require transparency, such as OHP, but also for obtaining high color density and good color development gloss even when applied to recording media such as photo glossy paper. It is.

  The average primary particle diameter of the vapor phase silica is preferably 50 nm or less, more preferably 20 nm or less, particularly preferably 10 nm or less, and most preferably 3 to 10 nm. Vapor phase silica is easy to adhere to each other due to hydrogen bonds with silanol groups, so that when the average primary particle size is 50 nm or less, it can form a structure with a large porosity, effectively improving ink absorption characteristics. Can be made.

  Silica fine particles may be used in combination with the other fine particles described above. When the other fine particles and the vapor phase silica are used in combination, the content of the vapor phase silica in all the fine particles is preferably 30% by mass or more, and more preferably 50% by mass or more.

As the inorganic fine particles, alumina fine particles, alumina hydrate, a mixture or a composite thereof are also preferable. Of these, alumina hydrate is preferable because it absorbs and fixes ink well, and pseudoboehmite (Al ₂ O ₃ .nH ₂ O) is particularly preferable. Alumina hydrates can be used in various forms, but it is preferable to use sol boehmite as a raw material because a smooth layer can be easily obtained.

  About the pore structure of pseudo boehmite, the average pore radius is preferably 1 to 25 nm, and more preferably 2 to 10 nm. The pore volume is preferably 0.3 to 2.0 ml / g, more preferably 0.5 to 1.5 ml / g. Here, the pore radius and the pore volume are measured by a nitrogen adsorption / desorption method, and can be measured using, for example, a gas adsorption / desorption analyzer (for example, trade name “Omni Soap 369” manufactured by Coulter).

  Among the alumina fine particles, vapor-phase method alumina fine particles are preferable because of their large specific surface area. The average primary particle diameter of the vapor phase alumina fine particles is preferably 50 nm or less, and more preferably 20 nm or less. Furthermore, colloidal silica having an average primary particle size of 50 nm or less is also preferable.

  The above-mentioned fine particles are, for example, JP-A-10-81064, JP-A-10-119423, JP-A-10-157277, JP-A-10-217601, JP-A-11-348409, JP-A-2001-138621, JP-A-2000-43401. 2000-212235, 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, 8-2090, 8-2091, The embodiments disclosed in JP-A-8-2093, JP-A-8-174992, JP-A-11-192777, JP-A-2001-301314 and the like can also be preferably used.

-Water-soluble resin-
The ink-receiving layer preferably contains a water-soluble resin. Examples of the water-soluble resin include a polyvinyl alcohol resin [polyvinyl alcohol (PVA), acetoacetyl, which is a resin having a hydroxy group as a hydrophilic structural unit. Modified polyvinyl alcohol, cation modified polyvinyl alcohol, anion modified polyvinyl alcohol, silanol modified polyvinyl alcohol, polyvinyl acetal, etc.], cellulose resin [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), Hydroxypropylcellulose (HPC), hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, etc.], chitins, chitosans, starch, ether Resin [polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyvinyl ether (PVE), etc.], resin having carbamoyl group [polyacrylamide (PAAM), polyvinyl pyrrolidone (PVP), poly Acrylic hydrazide, etc.]. Among these, polyvinyl alcohol resins, cellulose resins, resins having an ether bond, resins having a carbamoyl group, resins having a carboxyl group, and gelatins are preferable.
Moreover, the polyacrylic acid salt which has a carboxyl group as a dissociable group, maleic acid resin, alginate, gelatins, etc. can be mentioned.

  Among these, polyvinyl alcohol resin is particularly preferable. Examples of the polyvinyl alcohol include Japanese Patent Publication No. 4-52786, Japanese Patent Publication No. 5-67432, Japanese Patent Publication No. 7-29479, Japanese Patent No. 2537827, Japanese Patent Publication No. 7-57553, Japanese Patent No. 2502998, and Japanese Patent No. 3053231. JP-A-63-176173, JP-A-2604367, JP-A-7-276787, JP-A-9-207425, JP-A-11-58941, JP-A-2000-135858, JP-A-2001-205924, JP 2001-287444, JP 62-278080, JP 9-39373, JP 2750433, JP 2000-18801, JP 2001-213045, JP 2001-328345, JP 8 -324105, JP-A-11-348417, etc. It is below.

  These water-soluble resins may be used alone or in combination of two or more. As content of the said water-soluble resin, 9-40 mass% is preferable with respect to the total solid content mass of an ink receiving layer, and 12-33 mass% is more preferable.

The water-soluble resin and the fine particles mainly constituting the ink receiving layer of the ink jet recording medium may be a single material or a mixed system of a plurality of materials.
From the viewpoint of maintaining transparency, the type of water-soluble resin combined with the fine particles, particularly silica fine particles, is important. When the gas phase method silica is used, the water-soluble resin is preferably a polyvinyl alcohol resin, more preferably a polyvinyl alcohol resin having a saponification degree of 70 to 100%, and a saponification degree of 80 to 99.5. % Of polyvinyl alcohol resin is particularly preferable.

The polyvinyl alcohol-based resin has a hydroxyl group in its structural unit, and since this hydroxyl group and the surface silanol group of the silica fine particle form a hydrogen bond, a three-dimensional network having a secondary particle of the silica fine particle as a network chain unit. It becomes easy to form a structure. By forming this three-dimensional network structure, it is considered that a porous ink receiving layer having a high porosity and sufficient strength is formed.
In ink jet recording, the porous ink receiving layer obtained as described above can absorb ink rapidly by a capillary phenomenon, and can form dots with good roundness without ink bleeding.

  In addition, the polyvinyl alcohol resin may be used in combination with the other water-soluble resin. When the other water-soluble resin and the polyvinyl alcohol resin are used in combination, the content of the polyvinyl alcohol resin in the total water-soluble resin is preferably 50% by mass or more, and more preferably 70% by mass or more.

<Content ratio of fine particles and water-soluble resin>
The mass ratio [PB ratio; = x / y] of the mass (x) of the fine particles and the mass (y) of the water-soluble resin greatly affects the film structure and film strength of the ink receiving layer. That is, as the mass ratio (PB ratio) increases, the porosity, pore volume, and surface area (per unit mass) increase, but the density and strength tend to decrease.
As the PB ratio (x / y) in the ink receiving layer, the decrease in film strength and cracking during drying caused by the PB ratio being too large are prevented, and the PB ratio is too small, From the viewpoint of preventing the ink absorbability from being lowered due to the void being easily blocked by the resin and decreasing the porosity, 1.5 to 10 is preferable.

  In addition, since stress may be applied to the ink jet recording medium when passing through the transport system of the ink jet printer, the ink receiving layer needs to have sufficient film strength and is cut into a sheet shape. In addition, the ink receiving layer needs to have sufficient film strength from the viewpoint of preventing the ink receiving layer from cracking or peeling. In consideration of these, the PB ratio is more preferably 5 or less, and more preferably 2 or more from the viewpoint of ensuring high-speed ink absorbability in an inkjet printer.

For example, a coating solution in which gas phase method silica fine particles having an average primary particle size of 20 nm or less and a water-soluble resin are completely dispersed in an aqueous solution at a PB ratio (x / y) of 2 to 5 is applied on a support and dried. In this case, a three-dimensional network structure in which the secondary particles of silica fine particles are network chains is formed, the average pore diameter is 25 nm or less, the porosity is 50 to 80%, the pore specific volume is 0.5 ml / g or more, A translucent porous film having a specific surface area of 100 m ² / g or more can be easily formed.

-Crosslinking agent-
The ink receiving layer is a porous layer in which a coating layer containing fine particles and a water-soluble resin further contains a crosslinking agent capable of crosslinking the water-soluble resin, and is cured by a crosslinking reaction between the crosslinking agent and the water-soluble resin. Some embodiments are preferred.

Boron compounds are preferred for crosslinking the water-soluble resin, particularly polyvinyl alcohol resin. Examples of the boron compound include borax, boric acid, borate (for example, orthoborate, InBO ₃ , ScBO ₃ , YBO ₃ , LaBO ₃ , Mg ₃ (BO ₃ ) ₂ , Co ₃ (BO ₃ ) ₂ , two Borate (eg, Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborate (eg, LiBO ₂ , Ca (BO ₂ ) ₂ , NaBO ₂ , KBO ₂ ), tetraborate (eg, Na _{2 B 4 O 7 · 10H 2} O), can be mentioned five borate _{(e.g., KB 5 O 8 · 4H 2} O, Ca 2 B 6 O 11 · 7H 2 O, CsB 5 O 5) or the like. Among them, Of these, borax, boric acid, and borate are preferable, and boric acid is particularly preferable in that a crosslinking reaction can be promptly caused.

As the crosslinking agent for the water-soluble resin, the following compounds other than the boron compound may be used.
For example, aldehyde compounds such as formaldehyde, glyoxal, and glutaraldehyde; ketone compounds such as diacetyl and cyclopentanedione; bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1,3,5- Active halogen compounds such as triazine and 2,4-dichloro-6-S-triazine sodium salt; divinylsulfonic acid, 1,3-vinylsulfonyl-2-propanol, N, N′-ethylenebis (vinylsulfonylacetamide) ), Active vinyl compounds such as 1,3,5-triacryloyl-hexahydro-S-triazine; N-methylol compounds such as dimethylolurea and methyloldimethylhydantoin; melamine resins (for example, methylolmelamine, alkylated methylolmelamine) ;Epoxy resin;

Isocyanate compounds such as 1,6-hexamethylene diisocyanate; aziridine compounds described in US Pat. Nos. 3,017,280 and 2,983611; carboximide compounds described in US Pat. No. 3,100,704; glycerol triglycidyl Epoxy compounds such as ether; Ethyleneimino compounds such as 1,6-hexamethylene-N, N′-bisethyleneurea; Halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid; 2,3-dihydroxy Dioxane-based compounds such as dioxane; titanium-containing aluminum sulfate, chromium alum, potassium alum, metal-containing compounds such as zirconyl acetate, chromium acetate, polyamine compounds such as tetraethylenepentamine, hydrazide compounds such as adipic acid dihydrazide, A low molecule or polymer containing two or more oxazoline groups.
The crosslinking agents may be used alone or in combination of two or more.

  Crosslinking curing is performed by adding a crosslinking agent to a coating solution (hereinafter sometimes referred to as “coating solution A”) containing fine particles, a water-soluble resin and / or the following basic solution, and (1) the coating solution At the same time when A is applied to form the coating layer, or (2) anytime during the drying of the coating layer formed by coating the coating liquid A and before the coating layer exhibits reduced-rate drying Further, it is preferable to carry out by applying a basic solution having a pH of 7.1 or higher (hereinafter sometimes referred to as “coating liquid B”) to the coating layer.

The application of the cross-linking agent is preferably performed as follows when a boron compound is taken as an example. That is, when the ink receiving layer is a layer obtained by crosslinking and curing a coating layer coated with a coating solution (coating solution A) containing a water-soluble resin containing fine particles and polyvinyl alcohol, crosslinking curing is performed by (1) At the same time that the coating layer is formed by coating the liquid A, (2) any one of the coating layers formed by coating the coating solution A and before the coating layer exhibits reduced-rate drying. Sometimes, it is performed by applying a basic solution (coating solution B) having a pH of 7.1 or higher to the coating layer. The boron compound as a cross-linking agent may be contained in either the coating solution A or the coating solution B, and may be contained in both the coating solution A and the coating solution B.
1-50 mass% is preferable with respect to water-soluble resin, and, as for the usage-amount of a crosslinking agent, 5-40 mass% is more preferable.

(mordant)
The ink receiving layer according to the present invention preferably contains at least one selected from polyallylamine and derivatives thereof, and polyvinylamine and derivatives thereof as a mordant. These organic mordants may be contained as a copolymer copolymerized with other copolymerizable monomers. The polyallylamine in the present invention represents a product obtained by polymerizing monoallylamines (including salts).

  Of the organic mordants, compounds having a weight average molecular weight of 500 to 100,000 are preferable from the viewpoint of preventing blurring with time and improving ink absorbability of the ink receiving layer.

  As polyallylamine and derivatives thereof, various known allylamine polymers and derivatives thereof can be used. Examples of such derivatives include salts of polyallylamine and acids (acids include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid, methanesulfonic acid, toluenesulfonic acid, acetic acid, propionic acid, cinnamic acid, (meth) Organic acids such as acrylic acid, or combinations thereof, or salts of only a part of allylamine), derivatives of polyallylamine by polymer reaction, copolymers of polyallylamine and other copolymerizable monomers Specific examples of the monomer include (meth) acrylic acid esters, styrenes, (meth) acrylamides, acrylonitrile, vinyl esters and the like.

  The structure of these polyallylamine derivatives is not particularly limited, but the obtained polymer is preferably soluble in an organic solvent that is water-soluble or miscible with water, but also in the form of water-dispersible latex particles. Can be used.

  Specific examples of polyallylamine and derivatives thereof include JP-B-62-31722, JP-B-2-14364, JP-B-63-43402, JP-A-63-43403, JP-A-63-45721, JP-A-63-29881, Japanese Patent Publication No. 1-26362, No. 2-56365, No. 2-57084, No. 4-41686, No. 6-2780, No. 6-45649, No. 6-15592, No. 4-68622, Patents No. 3199227, No. 3008369, JP-A No. 10-330427, No. 11-21321, JP-A No. 2000-281728, No. 2001-106736, JP-A No. 62-256801, JP-A No. 7-173286, 7-213897, 9-235318, 9-302026, 11-21321, WO99 / 21901 , No. WO99 / 19372, JP-A-5-140213, compounds described in JP Kohyo No. 11-506488, and the like.

Various known polyvinylamines and their derivatives can be used as the polyvinylamine and its derivatives. Such a derivative is the same as the derivative of polyallylamine. Specific examples of polyvinylamine and derivatives thereof include JP-B-5-35162, JP-A-5-35163, JP-A-5-35164, JP-A-5-88846, JP-A-7-118333, JP-A-2000-344990, Examples thereof include compounds described in Japanese Patent Nos. 2648847 and 2666177.
Of these, polyallylamine and derivatives thereof are particularly preferable.

In the present invention, the following other mordants may be used in combination with the organic mordant in order to improve the water resistance and aging resistance of the formed image.
As the other mordant, a cationic polymer (cationic mordant) or an inorganic mordant is preferable as the organic mordant, and the liquid mordant having an anionic dye as a coloring material can be obtained by making the mordant present in the ink receiving layer. It can interact with each other to stabilize the coloring material and improve water resistance and aging resistance. The organic mordant and the inorganic mordant may be used alone or in combination with the organic mordant and the inorganic mordant.

The mordant is present so that the thickness of the mordant-existing portion from the surface of the receiving layer is 10 to 60%, preferably 20 to 40% with respect to the thickness of the receiving layer. If this is less than 10%, aging blur may increase, and if it exceeds 60%, the color density and ozone resistance may decrease.
Examples of the method for adjusting the thickness of the mordant-existing portion to the above range include (1) a method of forming a coating layer containing fine particles and a water-soluble resin and applying a mordant-containing solution, and (2) including fine particles and a water-soluble resin. The coating solution and the mordant-containing solution can be formed by an arbitrary method such as a method of applying multiple layers. Further, inorganic fine particles, a water-soluble resin, a crosslinking agent and the like may be contained in the mordant-containing solution.

As the cationic mordant, a polymer mordant having a primary to tertiary amino group or a quaternary ammonium base as a cationic group is preferably used, but a cationic non-polymer mordant may also be used. it can.
Examples of the polymer mordant include a homopolymer of a monomer having a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base (mordant monomer), and the mordant monomer and other monomers (hereinafter, What is obtained as a copolymer or condensation polymer with "non-mordant monomer") is preferred. Moreover, these polymer mordants can be used in any form of a water-soluble polymer or water-dispersible latex particles.

In addition, allylamine, diallylamine, its derivatives, salts and the like can be used. Examples of such compounds include allylamine, allylamine hydrochloride, allylamine acetate, allylamine sulfate, diallylamine, diallylamine hydrochloride, diallylamine acetate, diallylamine sulfate, diallylmethylamine and salts thereof (for example, Hydrochloride, acetate, sulfate, etc.), diallylethylamine and salts thereof (for example, hydrochloride, acetate, sulfate, etc.), diallyldimethylammonium salt (chloride, acetic acid as counter anions of the salt) Ion sulfate ions, etc.). In addition, since these allylamines and diallylamine derivatives are inferior in polymerizability in the form of amines, they are generally polymerized in the form of salts and desalted as required.
In addition, a unit such as N-vinylacetamide, N-vinylformamide or the like, which is converted into a vinylamine unit by hydrolysis after polymerization, and a salt thereof can also be used.

  The non-mordant monomer does not contain a basic or cationic moiety such as a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base, and does not show an interaction with a dye in an inkjet ink. Or the monomer which interaction is substantially small is said.

  In the ink jet recording medium, a coating layer composed of a coating liquid (first liquid) containing a first metal compound together with fine particles, a water-soluble resin, and the like is previously coated, and a second layer is further formed on the coating layer. By applying a basic solution (second liquid) having a pH of 7.1 or higher containing a metal compound, good film-forming properties capable of sufficiently performing hardening are obtained, and the first metal compound and the second metal are obtained. The compound (and other mordant components) acts as a mordant, and an ink, particularly a dye, is sufficiently mordanted to obtain an ink jet recording medium with excellent image print density and glossiness and less image bleed over time.

  The first metal compound contained in the first liquid is preferably an acidic metal compound, and examples thereof include polyvalent water-soluble metal salts and hydrophobic metal salt compounds. Specific examples include magnesium, aluminum, calcium, scandium, titanium, vanadium, manganese, iron, nickel, zirconium, copper, zinc, gallium, germanium, strontium, yttrium, molybdenum, indium, barium, lanthanum, cerium, praseodymium, neodymium. And salts or complexes of metals selected from samarium, europium, gadolinium, dysproprosium, erbium, ytterbium, hafnium, tungsten, bismuth.

  Specifically, for example, calcium acetate, calcium chloride, calcium formate, zirconium acetate, zirconium tetrachloride, calcium sulfate, barium acetate, barium sulfate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, manganese ammonium sulfate Hexahydrate, cupric chloride, ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate Tetrahydrate, nickel ammonium sulfate hexahydrate, nickel amidosulfate tetrahydrate, aluminum sulfate, aluminum alum, basic polyaluminum hydroxide, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate , Aluminum chloride hexahydrate Ferrous bromide, ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, zinc phenolsulfonate, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, zinc acetate Ammonium, zinc ammonium carbonate, titanium tetrachloride, tetraisopropyl titanate, titanium acetylacetonate, titanium lactate, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate nonahydrate, sodium phosphotungstate , Sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, gallium nitrate, germanium nitrate, strontium nitrate, yttrium acetate, yttrium chloride, Yttrium nitrate, indium nitrate, orchid nitrate Tan, lanthanum chloride, lanthanum acetate, lanthanum benzoate, cerium chloride, cerium sulfate, cerium octylate, praseodymium nitrate, neodymium nitrate, samarium nitrate, europium nitrate, gadolinium nitrate, dysprosium nitrate, erbium nitrate, ytterbium nitrate, hafnium chloride, nitric acid Bismuth etc. are mentioned. Among these, aluminum sulfate, aluminum alum, basic polyaluminum hydroxide, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, zirconium nitrate, and zirconium tetrachloride are preferable.

  It is preferable that two or more kinds of the first metal compounds are contained in the first liquid. Since the metal compound has a different mordanting dye depending on the type, the mordanting ability can be enhanced by using two or more types of the first metal compound. Therefore, more specifically, it is preferable to contain a metal compound corresponding to two or more dyes to be mordanted. Various combinations are conceivable as the metal compound corresponding to the dye. For example, a zirconium compound is effective for a black dye of a general ink.

  As content in the 1st liquid of a said 1st metal compound, 0.01-1 mass% is preferable with respect to the total mass of a 1st liquid, More preferably, it is 0.05-0.8 mass%. . By setting the content of the first metal compound in the above-described range, an ink jet recording medium can be produced in which curling under low humidity conditions is not deteriorated and the aging of the image is small. In addition, when using together the other mordant component mentioned later, total amount is in the said range, Comprising: It can contain in the range which does not impair the effect of this invention.

  As the second metal compound contained in the second liquid, those which are stable under basic conditions can be used without limitation. The metal compound may be a metal salt, a metal complex compound, an inorganic oligomer, or an inorganic polymer. . As said metal compound, what is mentioned as an inorganic mordant mentioned later is used preferably. Of these, zirconium compounds, aluminum compounds and zinc compounds are preferable, and zirconium compounds are particularly preferable. Examples include zirconyl ammonium carbonate, zirconium ammonium nitrate, potassium zirconium carbonate, zirconium ammonium citrate, zirconyl stearate, zirconyl octylate, zirconyl nitrate, zirconium oxychloride, and zirconium zirconium chloride, with zirconyl ammonium carbonate being particularly preferred. Moreover, you may use together the other mordant component mentioned later for the 2nd liquid as needed.

  In addition, as the metal complex compound, the metal complex described in “Chemical Review No. 32 1981” edited by the Chemical Society of Japan and “Coordination Chemistry Review”, Vol. 84, pages 85-277 (1988). And transition metal complexes containing a transition metal such as ruthenium described in JP-A-2-182701 can be used.

  The content of the second metal compound in the second liquid is preferably 0.1 to 0.8 mass%, more preferably 0.2 to 0.5 mass%, based on the total mass of the second liquid. It is. By setting the content of the second metal compound in the above range, the gloss can be improved without deteriorating bronzing. In addition, when using together the other mordant component mentioned later, total amount is in the said range, Comprising: It can contain in the range which does not impair the effect of this invention.

  The second liquid preferably further contains a basic compound. Examples of the basic compound include ammonium salts of weak acids, alkali metal salts of weak acids (lithium carbonate, sodium carbonate, potassium carbonate, lithium acetate, sodium acetate, potassium acetate, etc.), alkaline earth metal salts of weak acids (magnesium carbonate, carbonates). Barium, magnesium acetate, barium acetate, etc.), alkali metal or alkaline earth metal hydroxide, hydroxyammonium, ammonia, primary to tertiary amines (ethylamine, dimethylamine, triethylamine, polyallylamine, tripropylamine, tributylamine, Trihexylamine, dibutylamine, butylamine, N-ethyl-N-methylbutylamine, etc.), primary to tertiary anilines (diethylaniline, dibutylaniline, ethylaniline, aniline, etc.), pyridine which may have a substituent ( - aminopyridine, 3-aminopyridine, 4-aminopyridine, 4- (2-hydroxyethyl) -, etc. aminopyridine) but the like, ammonium salts of weak acids are particularly preferred.

  The weak acid is an inorganic acid or an organic acid described in Chemical Handbook Fundamentals II (Maruzen Co., Ltd.) or the like and having an pKa of 2 or more. Examples of the weak acid ammonium salt include ammonium carbonate, ammonium hydrogen carbonate, ammonium borate, and ammonium acetate. However, it is not limited to these. Among these, ammonium carbonate, ammonium hydrogen carbonate, and ammonium carbamate are preferable, and are effective in that ink bleeding can be reduced without remaining in the layer after drying. Two or more basic compounds may be used in combination.

  As content in the 2nd liquid of the said basic compound, 0.5-10 mass% is preferable with respect to the total mass containing the solvent of a 2nd liquid, More preferably, it is 1-5 mass%. When the content of the basic compound is particularly in the above range, a sufficient degree of curing can be obtained, and the ammonia concentration becomes too high and the working environment is not impaired.

A phenolic compound may be contained in the ink receiving layer, and in this case, an organic acid or an inorganic acid may be added. The acid may be mixed with a phenolic compound in advance, or a coating solution containing a phenolic compound may be applied simultaneously or at the same time and mixed.
By adding an acid, the surface pH of the ink receiving layer is adjusted to 3 to 8, preferably 5 to 7.5. This is preferable because yellowing resistance of the white background portion is improved. The surface pH is measured by the A method (coating method) of the surface pH measurement determined by the Japan Paper Pulp Technology Association (J.TAPPI). For example, the measurement can be performed using a pH measurement set for paper “model MPC” manufactured by Kyoritsu Riken Co., Ltd. corresponding to the method A.

-Other ingredients-
The sheet-like material according to the present invention may further contain various known additives, for example, ultraviolet absorbers, antioxidants, fluorescent brighteners, monomers, polymerization initiators, polymerization inhibitors, anti-bleeding agents, antiseptics, if necessary. Agents, viscosity stabilizers, antifoaming agents, surfactants, antistatic agents, matting agents, anti-curl agents, water-proofing agents, and the like.

Other components may be used alone or in combination of two or more. Other components may be added after being water-solubilized, dispersed, polymer-dispersed, emulsified or formed into oil droplets, or may be encapsulated in microcapsules. The amount of addition when other components are added is preferably 0.01 to 10 g / m ² .

  Further, for the purpose of improving the dispersibility of the inorganic fine particles, the inorganic surface may be treated with a silane coupling agent. The silane coupling agent includes an organic functional group (for example, a vinyl group, an amino group, an epoxy group, a mercapto group, a chloro group, an alkyl group, a phenyl group, an ester group, etc.) in addition to a coupling treatment site. Those having the following are preferred.

  In the present invention, the ink receiving layer coating solution preferably contains a surfactant. As the surfactant, any of cationic, anionic, nonionic, amphoteric, fluorine and silicon surfactants can be used.

  Examples of the nonionic surfactant include polyoxyalkylene alkyl ethers and polyoxyalkylene alkyl phenyl ethers (for example, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyalkylene ether) Ethylene nonylphenyl ether), oxyethylene / oxypropylene block copolymer, sorbitan fatty acid esters (for example, sorbitan monolaurate, sorbitan monooleate, sorbitan trioleate, etc.), polyoxyethylene sorbitan fatty acid esters (for example, polyoxyethylene) Sorbitan monolaurate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitant Oleate, etc.), polyoxyethylene sorbitol fatty acid esters (eg, polyoxyethylene sorbitol tetraoleate), glycerin fatty acid esters (eg, glycerol monooleate), polyoxyethylene glycerin fatty acid esters (polyoxymonostearate) Ethylene glycerol, monooleic acid polyoxyethylene glycerin, etc.), polyoxyethylene fatty acid esters (polyethylene glycol monolaurate, polyethylene glycol monooleate, etc.), polyoxyethylene alkylamine, acetylene glycols (eg, 2, 4, 7) , 9-tetramethyl-5-decyne-4,7-diol, and ethylene oxide adducts and propylene oxide adducts of the diols), and the like. Sharp emission alkyl ethers are preferable. The nonionic surfactant may be contained in the ink receiving layer coating solution.

  Examples of the amphoteric surfactant include amino acid type, carboxyammonium betaine type, sulfoammonium betaine type, ammonium sulfate betaine type, imidazolium betaine type, and the like, for example, US Pat. No. 3,843,368, Those described in JP-A-59-49535, JP-A-63-236546, JP-A-5-303205, JP-A-8-262742, and JP-A-10-282619 can be suitably used. As the amphoteric surfactant, an amino acid type amphoteric surfactant is preferable, and as the amino acid type amphoteric surfactant, as described in JP-A-5-303205, for example, an amino acid (glycine, glutamic acid, Histidine acid etc.) and N-aminoacyl acids and salts thereof into which long chain acyl groups have been introduced.

Examples of the anionic surfactant include fatty acid salts (for example, sodium stearate, potassium oleate), alkyl sulfate esters (for example, sodium lauryl sulfate, triethanolamine lauryl sulfate), and sulfonates (for example, sodium dodecylbenzenesulfonate). Alkyl sulfosuccinate (for example, sodium dioctyl sulfosuccinate), alkyl diphenyl ether disulfonate, alkyl phosphate, and the like.
Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, pyridinium salts, imidazolium salts, and the like.

  Examples of the fluorosurfactant include compounds derived via an intermediate having a perfluoroalkyl group using a method such as electrolytic fluorination, telomerization, or oligomerization. Examples thereof include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl trialkyl ammonium salts, perfluoroalkyl group-containing oligomers, and perfluoroalkyl phosphate esters.

  The silicone surfactant is preferably a silicone oil modified with an organic group, and can have a structure in which a side chain of a siloxane structure is modified with an organic group, a structure in which both ends are modified, or a structure in which one end is modified. Examples of the organic group modification include amino modification, polyether modification, epoxy modification, carboxyl modification, carbinol modification, alkyl modification, aralkyl modification, phenol modification, and fluorine modification.

  The content of the surfactant in the ink receiving layer coating solution is preferably 0.001 to 2.0%, more preferably 0.01 to 1.0%.

  The ink-receiving layer is formed by applying a coating solution containing fine particles and a water-soluble resin to the support surface to form a coating layer, and further adding a crosslinking agent to the coating solution and / or the following basic solution, and ( 1) at the same time when the coating solution is applied to form a coating layer, or (2) during the drying of the coating layer formed by coating the coating solution and before the coating layer exhibits reduced-rate drying, In any case, it is preferably formed by a method (Wet-on-Wet method) in which a basic solution having a pH of 7.1 or higher is applied to the coating layer and the coating layer is crosslinked and cured. Here, the crosslinking agent capable of crosslinking the water-soluble resin is preferably contained in at least one or both of the coating solution and the basic solution. Providing the ink-receiving layer crosslinked and cured in this manner is preferable from the viewpoint of ink absorbability and prevention of film cracking.

  The mordant is present such that the thickness of the mordant-existing portion from the surface of the receiving layer is 10 to 60% of the thickness of the receiving layer. For example, (1) a method of forming a coating layer containing the fine particles, a water-soluble resin, and a crosslinking agent, and applying a mordant-containing solution thereon, (2) a coating solution containing the fine particles, a water-soluble resin, and a mordant-containing solution. It can be formed by any method such as a method of applying multiple layers. The mordant-containing solution may contain inorganic fine particles, a water-soluble resin, a crosslinking agent, and the like.

  As described above, since a large amount of mordant is present in a predetermined portion of the ink receiving layer, the ink-jet coloring material is sufficiently mordanted, color density, aging blur, gloss of printed portion, and water resistance of characters and images after printing. This is preferable because ozone resistance is improved. Part of the mordant may be contained in the layer initially provided on the support, and in that case, the mordant to be applied later may be the same or different.

In the present invention, the ink-receiving layer coating solution (coating solution A) containing fine particles (for example, vapor phase silica) and a water-soluble resin (for example, polyvinyl alcohol) is prepared, for example, as follows. Can do. That is,
Fine particles such as gas phase method silica and a dispersant are added to water (for example, silica fine particles in water are 10 to 20% by mass), and a high-speed rotating wet colloid mill (for example, “Clearmix” manufactured by M Technique Co., Ltd.) )), For example, at a high speed of 10,000 rpm (preferably 5000 to 20000 rpm), for example, for 20 minutes (preferably 10 to 30 minutes), and then dispersed in an aqueous polyvinyl alcohol (PVA) solution (for example, In order to obtain a PVA having a mass of about 1/3 of the phase silica, and dispersion is performed under the same rotation conditions as described above. In order to impart stability to the coating solution, it is preferable to adjust the pH to about 9.2 with aqueous ammonia or the like, or to use a dispersant. The obtained coating liquid is in a uniform sol state, and a porous ink-receiving layer having a three-dimensional network structure can be formed by coating this on a support by the following coating method and drying it.

  As a disperser used for obtaining the aqueous dispersion, various kinds of conventionally known dispersers such as a high-speed rotary disperser, a medium agitating disperser (ball mill, sand mill, etc.), an ultrasonic disperser, a colloid mill disperser, and a high pressure disperser. Although a disperser can be used, a medium stirring type disperser, a colloid mill disperser, or a high-pressure disperser is preferable from the viewpoint of efficiently dispersing the formed fine particles.

  Moreover, water, an organic solvent, or these mixed solvents can be used as a solvent in each process. Examples of the organic solvent that can be used for this coating include alcohols such as methanol, ethanol, n-propanol, i-propanol, and methoxypropanol, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran, acetonitrile, ethyl acetate, and toluene. It is done.

Furthermore, a chaotic polymer can be used as the dispersant. Examples of the chaotic polymer include the aforementioned mordants. It is also preferable to use a silane coupling agent as the dispersant.
The amount of the dispersant added to the fine particles is preferably 0.1 to 30% by mass, and more preferably 1 to 10% by mass.

  The ink receiving layer coating liquid is applied by a known coating method such as an extrusion die coater, an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, a bar coater, or the like. it can.

  A basic solution (coating solution B) is applied to the coating layer simultaneously with or after the coating of the coating solution for ink-receiving layer (coating solution A). You may give before it comes to show decremental drying. In other words, after the application of the ink receiving layer coating liquid (coating liquid A), the coating liquid B is preferably introduced while the coating layer exhibits constant rate drying. The coating liquid B may contain a mordant.

  Here, “before the coating layer comes to show reduced drying” usually refers to a process for several minutes immediately after the coating of the coating liquid for the ink-receiving layer. This shows a phenomenon of “constant rate drying” in which the content of the solvent (dispersion medium) of the ink decreases in proportion to time. About the time which shows this "constant rate drying", it describes in chemical engineering handbook (pages 707-712, Maruzen Co., Ltd. issue, October 25, 1980), for example.

  As described above, after the coating liquid A is applied, the coating layer is dried until the coating layer exhibits a reduced rate of drying. This drying is generally performed at 40 to 180 ° C. for 0.5 to 10 minutes (preferably, 0 .5-5 minutes). The drying time naturally varies depending on the coating amount, but the above range is usually appropriate.

  As a method of giving before the said 1st application layer comes to show a decreasing rate drying rate, (1) The method of further apply | coating the coating liquid B on an application layer, (2) Spraying by methods, such as spraying. And (3) a method of immersing the support on which the coating layer is formed in the coating solution B, and the like.

  In the method (1), examples of the coating method for coating the coating liquid B include a curtain flow coater, an extrusion die coater, an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, and a bar. A known coating method such as a coater can be used. However, it is preferable to use a method in which the coater does not directly contact the already formed first coating layer, such as an extrusion die coater, a curtain flow coater, a bar coater or the like.

  After application of the coating liquid B, it is generally heated at 40 to 180 ° C. for 0.5 to 30 minutes, and dried and cured. Especially, it is preferable to heat at 40-150 degreeC for 1 to 20 minutes.

  When the basic solution (coating liquid B) is applied simultaneously with the application of the ink-receiving layer coating liquid (coating liquid A), the coating liquid A and the coating liquid B are brought into contact with the support. Thus, the ink receiving layer can be formed by simultaneously coating (multilayer coating) on the support, followed by drying and curing.

  The simultaneous coating (multilayer coating) can be performed by a coating method using, for example, an extrusion die coater or a curtain flow coater. After the simultaneous coating, the formed coating layer is dried. In this case, the drying is generally performed by heating the coating layer at 40 to 150 ° C. for 0.5 to 10 minutes, preferably 40 to 100. It is carried out by heating at a temperature of 0.5 to 5 minutes.

  When the simultaneous coating (multilayer coating) is performed by, for example, an extrusion die coater, the two types of coating liquid discharged at the same time are close to the discharge port of the extrusion die coater, that is, before moving onto the support. A multilayer is formed, and in that state, the multilayer is applied on the support. Since the two-layer coating liquid layered before coating is likely to cause a cross-linking reaction at the interface between the two liquids when transferred to the support, the two liquids to be ejected are mixed in the vicinity of the discharge port of the extrusion die coater. As a result, thickening is likely to occur, which may hinder the application operation. Therefore, when applying simultaneously as described above, it is preferable to apply the coating solution A and the coating solution B together with the barrier layer solution (intermediate layer solution) interposed between the two solutions to apply the triple layer simultaneously.

  The barrier layer solution can be selected without particular limitation. For example, an aqueous solution containing a trace amount of water-soluble resin, water, and the like can be given. The water-soluble resin is used in consideration of applicability for the purpose of a thickener and the like. For example, a cellulose resin (for example, hydroxypropylmethylcellulose, methylcellulose, hydroxyethylmethylcellulose) And polymers such as polyvinylpyrrolidone and gelatin. The barrier layer liquid may contain the mordant.

  After the ink receiving layer is formed on the support, the ink receiving layer is subjected to, for example, super calender, gloss calender, etc., and is subjected to calender treatment through the roll nip under heat and pressure, so that surface smoothness, glossiness, It is possible to improve transparency and coating strength. However, since the calendar process may cause a decrease in the porosity (that is, the ink absorbability may be decreased), it is necessary to set conditions under which the decrease in the porosity is small.

As roll temperature in the case of performing a calendar process, 30-150 degreeC is preferable and 40-100 degreeC is more preferable.
Moreover, as linear pressure between rolls at the time of a calendar process, 50-400 kg / cm is preferable and 100-200 kg / cm is more preferable.

The layer thickness of the ink receiving layer needs to be determined in relation to the void ratio in the layer since it needs to have an absorption capacity sufficient to absorb all droplets when used for inkjet recording. For example, when the ink amount is 8 nL / mm ² and the porosity is 60%, the layer thickness is preferably about 15 μm or more.
Considering this point, when used for inkjet recording, the thickness of the ink receiving layer is preferably 10 to 50 μm.

The pore diameter of the ink receiving layer is preferably 0.005 to 0.030 μm, more preferably 0.01 to 0.025 μm in terms of median diameter.
The porosity and pore median diameter can be measured using a mercury porosimeter (trade name “Bore Sizer 9320-PC2” manufactured by Shimadzu Corporation).

In addition, the ink receiving layer is preferably excellent in transparency, as a guide, the haze value when the ink receiving layer is formed on a transparent film support is preferably 30% or less, More preferably, it is 20% or less.
The haze value can be measured using a haze meter (HGM-2DP: Suga Test Instruments Co., Ltd.).

  A polymer fine particle dispersion may be added to a constituent layer (for example, an ink receiving layer or a back layer) of the ink jet recording medium obtained by the present invention. This polymer fine particle dispersion is used for the purpose of improving film properties such as dimensional stabilization, curling prevention, adhesion prevention, and film cracking prevention. The polymer fine particle dispersion is described in JP-A Nos. 62-245258, 62-1316648, and 62-110066. If a polymer fine particle dispersion having a low glass transition temperature (40 ° C. or lower) is added to the layer containing the mordant, cracking and curling of the layer can be prevented. Further, even when a polymer fine particle dispersion having a high glass transition temperature is added to the back layer, curling can be prevented.

Next, an image recording medium other than the ink jet recording medium will be described.
-Image receiving material for electrophotography-
The electrophotographic image-receiving material has an image recording medium support and at least one toner image-receiving layer (image recording layer) provided on at least one surface of the support. Layer, for example, surface protective layer, intermediate layer, undercoat layer, cushion layer, charge control (prevention) layer, reflection layer, color adjustment layer, storage stability improvement layer, adhesion prevention layer, anti-curl layer, smoothing layer, etc. Have. Each of these layers may have a single layer structure or a laminated structure.

-Silver salt photographic material-
As the silver salt photographic light-sensitive material, for example, a silver halide photographic sheet having a structure in which a photosensitive layer (image recording layer) that develops at least YMC color is provided on a support for an image recording medium, and subjected to printing exposure. And a material used in a silver halide photographic system for obtaining an image by performing color development, bleach-fixing, washing with water, and drying by passing through a plurality of processing tanks.

-Thermal transfer image receiving material-
The thermal transfer material has, for example, a structure in which at least a thermochromic layer (image recording layer) is provided on an image recording medium support, and a thermostat that forms an image by repeating heating with a thermal head and fixing with ultraviolet rays. And heat-sensitive color recording materials used in the autochrome method (TA method).

-Thermal color recording material-
The heat-sensitive color recording material has, for example, a structure in which at least a heat-meltable ink layer (image-recording layer) is provided on a support for an image recording medium, and is heated from a heat-meltable ink layer by a heat-sensitive head. Examples thereof include materials used in a system for melting and transferring ink onto an image-receiving sheet for thermal transfer recording.

-Sublimation transfer image receiving material-
The sublimation transfer image receiving material has a configuration in which an ink layer (image recording layer) containing at least a heat diffusible dye (sublimation dye) is provided on a support for an image recording medium, and is heated by a thermal head. Examples thereof include materials used in a sublimation transfer method in which a heat diffusible dye is transferred from an ink layer onto a thermal transfer recording image receiving sheet.

  In addition, the electrophotographic image-receiving material, heat-sensitive color-developing recording material, sublimation transfer image-receiving material, thermal transfer image-receiving material, or silver salt photographic light-sensitive material has at least an image recording layer (toner image-receiving layer, heat-meltable layer) corresponding to each material. An ink layer, an ink layer, a thermochromic layer, or a photosensitive layer) can be formed on the undercoat layer by a method similar to the above-described preparation of an ink jet recording medium.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In the examples, “parts” and “%” represent “parts by mass” and “mass%” unless otherwise specified, and “degree of polymerization” represents “degree of weight average polymerization”.

[Example 1]
(Production of support)
50 parts of LBKP made of acacia and 50 parts of LBKP made of aspen were beaten and adjusted to 300 ml of Canadian freeness by a disc refiner.

  Next, the pulp slurry obtained above was charged with 1.3% cationic starch (CATO 304L manufactured by NSC Japan), 0.15% anionic polyacrylamide (DA4104 manufactured by Seiko PMC Co., Ltd.), and alkyl ketene dimer. (Arakawa Chemical Size Pine K) 0.29%, epoxidized behenamide 0.29%, polyamide polyamine epichlorohydrin (Arakawa Chemical Co., Ltd .: Arafix 100) 0.32%, then added antifoaming agent 0.12% was added.

In the process of making the pulp slurry prepared as described above with a long paper machine and pressing the felt surface of the web against the drum dryer cylinder through the dryer canvas for drying, the tensile force of the dryer canvas is 1.6 kg / After drying at a setting of cm, 1 g / m ² of polyvinyl alcohol (manufactured by Kuraray Co., Ltd .: KL-118) was applied to both sides of the base paper with a size press and dried to perform calendar treatment. The base paper was made with a basis weight of 166 g / m ² to obtain a base paper (base paper) having a thickness of 160 μm.

After the corona discharge treatment was performed on the wire surface (back surface) side of the obtained base paper, high-density polyethylene was coated to a thickness of 25 μm using a melt extruder, and a thermoplastic resin layer comprising a mat surface was formed. (Hereinafter, this thermoplastic resin layer surface is referred to as “back surface”). The thermoplastic resin layer on the back side is further subjected to corona discharge treatment, and then, as an antistatic agent, aluminum oxide (“Alumina Sol 100” manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (manufactured by Nissan Chemical Industries, Ltd.) Of “Snowtex O”) was dispersed in water at a mass ratio of 1: 2 so that the dry mass was 0.2 g / m ² .

  Further, after the corona discharge treatment is performed on the felt surface (surface) side where the thermoplastic resin layer is not provided, 10% of anatase-type titanium dioxide and 0.3% of ultramarine manufactured by Tokyo Ink Co., Ltd. are contained. Low MFR (melt flow rate) of 3.8, adjusted to an amount of 0.08% of fluorescent whitening agent “Whitefloor PSN conc” manufactured by Nippon Chemical Industry Co., Ltd. Density polyethylene was extruded to a thickness of 25 μm using a melt extruder to form a high gloss thermoplastic resin layer on the surface side of the base paper (hereinafter, this high gloss thermoplastic resin layer surface is referred to as “front side And a support was prepared. This support was aligned to a width of 1.5 m and a winding length of 3000 m.

(Preparation of coating solution for ink receiving layer)
(1) Gas phase method silica fine particles in the following composition, (2) ion-exchanged water, and (3) “Charol DC-902P” are mixed together to produce KD-P (manufactured by Shinmaru Enterprises Co., Ltd.). After using and dispersing, a solution containing the following (4) polyvinyl alcohol (water-soluble resin), (5) boric acid, (6) polyoxyethylene lauryl ether, and (7) ion-exchanged water is added. A coating solution for an ink receiving layer was prepared. At this time, the mass ratio of the silica fine particles to the water-soluble resin (PB ratio = (1) :( 4)) is 4.5: 1, and the pH of the ink receiving layer coating solution is 3.5 and acidic. showed that.

<Composition of ink receiving layer coating solution>
(1) Gas phase method silica fine particles (inorganic fine particles) 10.0 parts (“Leosil QS30” manufactured by Tokuyama Corporation, average primary particle diameter: 7 nm)
(2) Ion-exchanged water 51.6 parts (3) “Charol DC-902P” (51.5% aqueous solution) 1.0 part (dispersant, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
(4) Polyvinyl alcohol (water-soluble resin) 8% aqueous solution 27.8 parts ("PVA124" manufactured by Kuraray Co., Ltd., saponification degree 98.5%, polymerization degree 2400)
(5) Boric acid (crosslinking agent) 0.4 part (6) Polyoxyethylene lauryl ether (surfactant) 1.2 part ("Emulgen 109P" (10% aqueous solution) manufactured by Kao Corporation, HLB value 13. 6)
(7) Ion exchange water 33.0 parts

(Production of long roll body)
The ink receiving layer coating liquid obtained above was applied to the front surface of the aligned support using an extrusion die coater at a coating amount of 200 ml / m ² (coating process), and 80 mm by a hot air dryer. The coating layer was dried at 20 ° C. (wind speed 3 to 8 m / sec) until the solid content concentration of the coating layer became 20%. This coating layer exhibited a constant rate of drying during this period. Immediately after that, it was immersed in a mordant solution having the following composition for 10 seconds to deposit 20 g / m ² on the coating layer (step of applying a mordant solution), and further dried at 80 ° C. for 10 minutes (drying step). . Thus, an ink receiving layer (recording layer) having a dry film thickness of 32 μm was applied. The sheet-like material that can be used as the ink jet recording medium has the same size as the support (width: 1.5 m, winding length: 3000 m), and a winding long roll body with the front side facing outward. The obtained long roll body was stored at normal temperature and humidity for 2 weeks.

<Composition of mordant solution>
(1) Boric acid (crosslinking agent) 0.65 parts (2) Polyallylamine “PAA-03” 20% aqueous solution 12.5 parts (Mordant, manufactured by Nittobo Co., Ltd.)
(3) Ion-exchanged water 72.0 parts (4) Ammonium chloride (surface pH adjuster) 0.8 parts (5) Polyoxyethylene lauryl ether (surfactant) 10.0 parts ("Kao Co., Ltd." Emulgen 109P ", 2% aqueous solution, HLB value 13.6)
(6) MegaFac "F1405" 10% aqueous solution 2.0 parts (Fluorine surfactant manufactured by Dainippon Ink & Chemicals, Inc.)

(Preparation of inkjet recording sheet (medium))
The long roll body stored at room temperature and normal humidity for 2 weeks was cut with the image recording medium manufacturing apparatus 12 shown in FIG. 1 to obtain an A6 size ink jet recording sheet. The correction mechanism 46 in the image recording medium manufacturing apparatus 12 uses a free roller having a diameter of 12 mm as the decurler rubber 80, the holding angle between the web 18 of the long roll body and the decurler rubber 80 is 55 °, and is conveyed at a tension of 40 kg / m. did.

[Example 2]
In the production of the ink jet recording sheet of Example 1, an ink jet recording sheet was obtained in the same manner as in Example 1 except that the decurler rubber 80 was changed to a free roller having a diameter of 8 mm.

Example 3
In the production of the ink jet recording sheet of Example 1, an ink jet recording sheet was obtained in the same manner as in Example 1 except that the decurler rubber 80 was changed to a free roller having a diameter of 16 mm.

Example 4
In the production of the ink jet recording sheet of Example 1, an ink jet recording sheet was obtained in the same manner as in Example 1 except that the tension was changed to 10 kg / m.

Example 5
In the production of the ink jet recording sheet of Example 1, an ink jet recording sheet was obtained in the same manner as in Example 1 except that the tension was changed to 90 kg / m.

Example 6
In the production of the support of Example 1, an inkjet recording sheet was obtained in the same manner as in Example 1 except that the thickness of the high density polyethylene coated on the back side of the base paper was changed to 23 μm.

Example 7
In the production of the support of Example 1, except that the thickness of the high-density polyethylene coated on the back side of the base paper was changed to 35 μm and the dry film thickness of the ink receiving layer was changed to 20 μm. In the same manner as in Example 1, an ink jet recording sheet was obtained.

Example 8
In the production of the support of Example 1, the basis weight of the base paper was made at 114 g / m ² and changed to obtain a base paper having a thickness of 110 μm, and the thickness of the high-density polyethylene coated on the back side of the base paper Was changed to 45 μm, and an ink jet recording sheet was obtained in the same manner as in Example 1 except that the thickness of the low density polyethylene extruded using a melt extruder to the front side of the base paper was changed to 50 μm. It was.

Example 9
In the production of the support of Example 1, the thickness of the high-density polyethylene coated on the back side of the base paper is changed to 23 μm, and the low-density polyethylene is extruded using a melt extruder on the front side of the base paper The ink jet recording sheet was obtained in the same manner as in Example 1 except that the thickness of the ink receiving layer was changed to 16 μm and the dry thickness of the ink receiving layer was changed to 40 μm.

[ Reference Example 1 ]
In the production of the support of Example 1, an inkjet recording sheet was obtained in the same manner as in Example 1 except that the thickness of the high-density polyethylene coated on the back side of the base paper was changed to 20 μm.

[ Reference Example 2 ]
In the production of the support of Example 1, an ink jet recording sheet was obtained in the same manner as in Example 1 except that the thickness of the high density polyethylene coated on the back side of the base paper was changed to 40 μm.

[ Reference Example 3 ]
Ink jet recording was carried out in the same manner as in Example 1 except that the thickness of the low density polyethylene extruded using a melt extruder on the front side of the base paper was changed to 14 μm in the production of the support of Example 1. A sheet was obtained.

Example 10
In the production of the support of Example 1, an ink jet recording sheet was obtained in the same manner as in Example 1 except that the amounts of LBKP made of acacia and LBKP made of aspen were changed to 28 parts and 72 parts.

Example 11
In Example 1, except that the ink receiving layer coating solution prepared and applied to the support was changed to the ink receiving layer coating solution B prepared as described below, and a long roll was prepared as described below. Obtained an inkjet recording sheet in the same manner as in Example 1.

(Preparation of coating liquid B for ink receiving layer)
(1) Gas phase method silica fine particles, (2) ion-exchanged water, (3) “Charol DC-902P”, and (4) “ZA-30” in the following composition are mixed, and KD-P ( After dispersion using Shinmaru Enterprises Co., Ltd., the dispersion was heated to 45 ° C. and held for 20 hours. Thereafter, the following (5) boric acid, (6) polyvinyl alcohol (water-soluble resin) solution, (7) “Superflex 600”, (8) polyoxyethylene lauryl ether, (9) ethanol, Was added at 30 ° C. to prepare a coating liquid B for ink receiving layer.
The mass ratio between the silica fine particles and the water-soluble resin (PB ratio = (1) :( 6)) is 4.5: 1, and the pH of the ink-receiving layer coating liquid B is 3.9, indicating acidity. It was.

<Composition of Ink Receiving Layer Coating Liquid B>
(1) Gas phase method silica fine particles (inorganic fine particles) 10.0 parts (“AEROSIL 300S F75” manufactured by Nippon Aerosil Co., Ltd.)
(2) Ion-exchanged water 64.8 parts (3) "Charol DC-902P" (51.5% aqueous solution) 0.87 parts (dispersant, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
(4) 0.54 parts “ZA-30” (Daiichi Rare Element Chemical Industries, Ltd.)
(5) Boric acid (crosslinking agent) 0.37 parts (6) Polyvinyl alcohol (water-soluble resin) solution 29.4 parts (7) “Superflex 600” 1.2 parts (Daiichi Kogyo Seiyaku ( Made by Co., Ltd.)
(8) 0.49 part of polyoxyethylene lauryl ether (surfactant) (“Emulgen 109P” (10% aqueous solution) manufactured by Kao Corporation, HLB value 13.6)
(9) Ethanol 2.5 parts

Composition of polyvinyl alcohol solution ・ 2.0 parts of polyvinyl alcohol (“PVA235” manufactured by Kuraray Co., Ltd., saponification degree 88%, polymerization degree 3500)
-Polyoxyethylene lauryl ether (surfactant) 0.03 part ("Emulgen 109P" (10% aqueous solution) manufactured by Kao Corporation, HLB value 13.6)
・ 0.06 parts of the following compound 1 ・ 0.68 parts of diethylene glycol monobutyl ether (“Butizenol 20P” manufactured by Kyowa Hakko Chemical Co., Ltd.)
・ Ion exchange water 26.6 parts

(Production of long roll body)
The ink receiving layer coating solution obtained above was applied to the front surface of the aligned support using an extrusion die coater at a coating amount of 173 ml / m ^2. A polyaluminum chloride aqueous solution obtained by diluting (Alphain 83, manufactured by Daimei Chemical Industry Co., Ltd.) five times was applied in-line at a rate of 10.8 ml / m ² (application step). It dried with the hot air dryer at 80 degreeC (wind speed 3-8 m / sec) until the solid content density | concentration of the application layer became 20%. This coating layer exhibited a constant rate of drying during this period. Immediately after that, it was immersed in a basic solution having the following composition for 10 seconds to deposit 13 g / m ² on the coating layer (step of applying a basic solution), and further dried at 80 ° C. for 10 minutes (drying) Process). Thus, an ink receiving layer (recording layer) having a dry film thickness of 32 μm was applied. The sheet-like material that can be used as the ink jet recording medium has the same size as the support (width: 1.5 m, winding length: 3000 m), and a winding long roll body with the front side facing outward. The obtained long roll body was stored at normal temperature and humidity for 2 weeks.

<Composition of basic solution>
(1) Boric acid (crosslinking agent) 0.65 parts (2) Zirconyl ammonium carbonate 2.5 parts (Zircosol AC-7 (28% aqueous solution), manufactured by Daiichi Rare Element Chemical Co., Ltd.)
(3) Ammonium carbonate 3.5 parts (1st grade, manufactured by Kanto Chemical Co., Inc.)
(4) Ion-exchanged water 63.3 parts (5) Polyoxyethylene lauryl ether (surfactant) 30.0 parts ("Emulgen 109P" manufactured by Kao Corporation, 2% aqueous solution, HLB value 13.6)

[Comparative Example 1]
In the production of the ink jet recording sheet of Example 1, an ink jet recording sheet was obtained in the same manner as in Example 1 except that the decurler rubber 80 was changed to a free roller having a diameter of 6 mm.

[Comparative Example 2]
In the production of the ink jet recording sheet of Example 1, an ink jet recording sheet was obtained in the same manner as in Example 1 except that the decurler rubber 80 was changed to a free roller having a diameter of 24 mm.

[Comparative Example 3]
In the production of the ink jet recording sheet of Example 1, an ink jet recording sheet was obtained in the same manner as in Example 1 except that the holding angle between the long roll web 18 and the decurler rubber 80 was changed to 65 °.

[Comparative Example 4]
Inkjet recording was carried out in the same manner as in Example 1 except that the long roll body coated with the ink receiving layer was wound up with the back side facing out (front side facing inward). A sheet was obtained.

[Evaluation test]
The following evaluation tests were conducted on the A6 size Examples 1-14 and Comparative Examples 1-4 obtained above. The evaluation results are shown in Table 1.

(1) Cracking of ink image-receiving layer Cracks were visually evaluated on the surface of the 1000 ink-receiving layer layers of the ink jet recording sheet obtained according to the following criteria.
A: No cracks are observed on the ink image-receiving layer surface.
B: Cracks were observed on the surface of the ink image-receiving layer, though very little.
C: Cracks were observed on the ink image-receiving layer surface.

(2) Curly curl The obtained inkjet recording sheet was curled on a flat surface after being stored for 24 hours under conditions of 23 ° C. 60% RH and 10 ° C. 20% RH with the ink image-receiving layer facing upward. The height of four raised corners was measured with the surface down, and curled curl was evaluated according to the following criteria. In the following evaluation criteria, “−” indicates that the ink is outcurled to the ink image receiving layer surface side, and “+” indicates that the ink is incurled to the ink image receiving layer surface side.
A: Each sample stored at 23 ° C. 60% RH and 10 ° C. 20% RH for 24 hours has a height of 4 corners within a range of −4 to +2 mm, and curl curl is good.
B: In the sample stored for 24 hours at 23 ° C. and 60% RH, the height of the four corners was within the range of −4 to +2 mm, but in the sample stored for 24 hours at 10 ° C. and 20% RH, less than −4 mm or +2 mm There are one or more corners exceeding, and curl curl under high temperature and high humidity is good.
C: Samples stored at 23 ° C. and 60% RH for 24 hours and samples stored at 10 ° C. and 20% RH for 24 hours have one or more corners of less than −4 mm or +2 mm, and curl curl is poor.

(3) Transportability with an ink jet printer Using an ink jet printer “PM-970C” manufactured by Seiko Epson Corporation, images of a landscape and a person are printed on the obtained ink jet recording sheet. The transportability with an inkjet printer was evaluated.
A: No ink contamination is observed in the image area.
B: Slight ink stains were observed at the edge of the image area.
C: Ink contamination was observed in the image area.

(4) Image clarity (glossiness)
About the white background part of the obtained inkjet recording sheet, according to JIS H8686, using Suga Test Instruments Co., Ltd. image clarity measuring machine "ICM-1M", an incident angle: 60 degree | times, a light reception angle: 60 degree | times, an optical comb width: The C value was determined under the condition of 2.0 mm, and the image clarity was evaluated according to the following criteria.
A: The C value was 80% or more.
B: The C value was 75% or more and less than 80%.
C: The C value was 70% or more and less than 75%.
D: The C value was less than 70%.

  From the results shown in Table 1, the ink jet recording sheet obtained by using the method for producing an image recording medium of the present invention does not cause cracking and curl curl of the ink image receiving layer, and is transportable by an ink jet printer. It can be seen that the image clarity is excellent.

It is side surface expansion explanatory drawing of the image recording medium manufacturing apparatus for enforcing the manufacturing method of the image recording medium of this invention. It is a schematic diagram for demonstrating a holding angle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Image recording medium manufacturing apparatus 18 Long roll web 18a Long roll body 40 Long roll body supply mechanism 42 Cutting mechanism 44 Conveying mechanism 46 Correction mechanism 50 Discarding part 56 Joining part 58 Rewinding roller 60 Feed roller 62 Nip roller 64 Nip roller pair 74 Slitter 76a Slitter upper blade 76b Slitter lower blade 78 Ear cutter 79 Control unit 80 Decal rubber (correcting member)
86a Fixed blade 86b Movable blade

Claims (8)

Winding a sheet-like material having a recording layer on one thermoplastic resin layer of a support provided with a thermoplastic resin layer on both sides on a paper substrate so that the surface having the recording layer faces outside. The web of the long roll body obtained by being unwound from the long roll body is fed to the cutting mechanism, and the correction member is pressed to the side of the web of the long roll body having the recording layer, thereby curling the web. A method of manufacturing an image recording medium that cuts while correcting,
The ratio of the thickness B of the thermoplastic resin layer on the side opposite to the side having the recording layer to the thickness A of the thermoplastic resin layer on the side having the recording layer formed by melt extrusion of the thermoplastic resin layer (B / A) is 0.9 to 1.5, and the side having the recording layer with respect to the sum of the thickness C of the recording layer and the thickness A of the thermoplastic resin layer on the side having the recording layer The ratio (B / (A + C)) of the thickness B of the thermoplastic resin layer on the opposite side to 0.4 is 0.8 to 0.8, and the straightening member is a roller having a diameter of 8 to 16 mm. The web of the long roll body is conveyed while correcting the curl of the web of the long roll body while holding the straightening member and the web of the long roll body so that the holding angle is less than 60 °. A method for producing an image recording medium, characterized in that: The method for manufacturing an image recording medium according to claim 1, wherein the holding angle is not less than 45 ° and less than 55 ° .   The method for producing an image recording medium according to claim 1 or 2, wherein a thickness A of the thermoplastic resin layer on the side having the recording layer is 15 to 60 µm.   The method for producing an image recording medium according to any one of claims 1 to 3, wherein the paper base contains 25% by mass or more of kraft pulp made of acacia.   The method for producing an image recording medium according to claim 1, wherein the recording layer is an ink receiving layer, and the image recording medium is an ink jet recording medium.   The method for producing an image recording medium according to claim 5, wherein the ink receiving layer contains a water-soluble resin, a crosslinking agent capable of crosslinking the water-soluble resin, fine particles, and a mordant. The water-soluble resin is at least one selected from the group consisting of a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, a resin having a carbamoyl group, a resin having a carboxyl group, and gelatin, and the fine particles are 7. The method for producing an image recording medium according to claim 6 , wherein the image recording medium is at least one selected from the group consisting of silica fine particles, colloidal silica, alumina fine particles, and pseudoboehmite.   The ink receiving layer is a layer obtained by crosslinking and curing a coating layer coated with a coating solution containing at least fine particles and a water-soluble resin, and the crosslinking and curing is performed by adding a crosslinking agent to the coating solution and / or the following basic solution. And (1) at the same time when the coating solution is applied to form a coating layer, or (2) during the drying of the coating layer formed by coating the coating solution, the coating layer is reduced. 8. The method according to claim 5, which is performed by applying a basic solution having a pH of 7.1 or higher to the coating layer at any time before exhibiting rate drying. A method for manufacturing an image recording medium.

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