JP4821671B2 - Multilayer coated sheet and method for producing the same - Google Patents

Description

  The present invention relates to a multilayer coated sheet having an anionic layer and a cationic layer, such as an inkjet recording sheet, and a method for producing the same.

  Ink jet recording method in which water-based ink is ejected from a fine nozzle toward a recording sheet and an image is formed on the recording surface of the sheet has less noise during recording, and it is easy to form a full-color image. It is widely used in terminal printers, facsimiles, plotters, form printing, and the like due to the fact that high-speed recording is possible and the recording cost is lower than other printing apparatuses.

As a recording sheet suitable for the ink jet recording method, an ink jet recording sheet having an ink receiving layer is widely used. The ink jet recording sheet is required to have both excellent ink drying and ink fixing properties in order to realize high image quality and high speed recording.
In order to satisfy this requirement, for example, in Patent Document 1, an ink receiving layer of an ink jet recording sheet, an ink absorbing layer containing fine particles and a binder, and an ink fixing containing fine particles, a binder and an ink fixing agent are used. It has been proposed to consist of layers.
Japanese Patent Laid-Open No. 10-71764

Usually, since the ink in the ink jet recording sheet is anionic, a cationic compound is used as the ink fixing agent in the ink fixing layer, and the coating liquid for forming the ink fixing layer is cationic. There were many things. On the other hand, since the fine particles in the ink absorption layer are often anionic, the coating liquid for forming the ink absorption layer is often anionic.
By the way, in order to manufacture a multilayer coating sheet in which a plurality of layers are formed on a support, simultaneous multilayer coating on the support using a slide bead coater, a curtain coater or the like for the purpose of simplifying the process. May be performed. However, in order to produce an ink jet recording sheet having the ink absorbing layer and the ink fixing layer as described above, a cationic ink fixing layer forming coating solution is simultaneously formed on the anionic ink absorbing layer forming coating solution. In the case of multilayer coating, the anionic fine particles and the cationic ink fixing agent reacted and aggregated. As a result, there are problems in that trouble occurs in the process and the quality of the obtained inkjet recording sheet is deteriorated.
In addition, in order to produce an ink jet recording sheet having an ink absorbing layer and an ink fixing layer as an ink receiving layer, an ink absorbing layer forming coating solution is applied on a support, and then the ink fixing is performed without drying. Even when a so-called wet-on-wet coating method for applying a layer forming coating solution was applied, agglomeration of fine particles and a cationic compound was observed as in the simultaneous multilayer coating method.

For these reasons, when an inkjet recording sheet having an ink absorbing layer and an ink fixing layer as an ink receiving layer is produced, a cationic ink fixing layer forming layer is formed on the anionic ink absorbing layer forming coating liquid. The method of coating the coating liquid without drying could not be taken. Therefore, conventionally, after coating the ink absorbing layer forming coating liquid on the support, drying to form the ink absorbing layer, coating the ink fixing layer forming coating liquid on the dried ink absorbing layer. Was. However, this manufacturing method has a problem that the number of drying steps increases, resulting in a decrease in productivity and an increase in cost.
The present invention has been made in view of the above circumstances, and despite having a cationic layer and an anionic layer, a multilayer coating sheet that can be produced with a small number of drying steps and is low in cost. The purpose is to provide. In addition, the number of drying steps when multilayer coating of an anionic coating liquid and a cationic coating liquid can be reduced, and the anionic compound in the anionic coating liquid and the cationic compound in the cationic coating liquid It aims at providing the manufacturing method of the multilayer coating sheet in which aggregation was prevented.

The present invention includes the following configurations.
[1] In a multilayer coating sheet having a support and a coating layer formed on the support,
A multilayer coating sheet, wherein the coating layer comprises an anionic layer, a cationic layer, and a nonionic intermediate layer formed between the anionic layer and the cationic layer.
[2] A method for producing a multilayer coating sheet by coating an anionic coating solution and a cationic coating solution on a support,
An anionic coating liquid is applied onto a support, and a nonionic intermediate layer forming coating liquid is applied onto the coated anionic coating liquid, and the applied intermediate layer forming coating liquid is applied. A method for producing a multilayer coated sheet, comprising coating a cationic coating liquid on the top.
[3] A method for producing a multilayer coating sheet by applying a cationic coating liquid and an anionic coating liquid on a support,
A cationic coating solution is applied onto the support, and a nonionic intermediate layer forming coating solution is applied onto the coated cationic coating solution, and the applied intermediate layer forming coating solution is applied. A method for producing a multilayer coated sheet, comprising coating an anionic coating liquid on the top.
[4] A method for producing a multilayer coating sheet by coating an anionic coating solution and a cationic coating solution on a support,
A method for producing a multilayer coating sheet, comprising simultaneously coating an anionic coating liquid, a nonionic intermediate layer-forming coating liquid, and a cationic coating liquid on a support.
[5] The method for producing a multilayer coated sheet according to any one of [2] to [4], wherein the anionic coating liquid and the cationic coating liquid contain fine particles, and the multilayer coated sheet is an inkjet recording sheet.

The multilayer coated sheet of the present invention can be produced with a small number of drying steps and has a low cost despite having a cationic layer and an anionic layer.
According to the method for producing a multilayer coating sheet of the present invention, the number of drying steps can be reduced despite the multilayer coating of an anionic coating liquid and a cationic coating liquid. Aggregation between the anionic compound and the cationic compound in the cationic coating liquid can be prevented.

An embodiment of the multilayer coated sheet of the present invention will be described taking an inkjet recording sheet as an example. However, the multilayer coated sheet of the present invention is not limited to an inkjet recording sheet.
In FIG. 1, the sheet | seat for inkjet recording which is a multilayer coating sheet of this embodiment is shown. The ink jet recording sheet 1 includes a support 10 and an ink receiving layer 20 that is a coating layer formed on the support 10. Further, the ink receiving layer 20 includes an anionic layer 21, a cationic layer 22, and a nonionic intermediate layer 23 formed between the anionic layer 21 and the cationic layer 22. Further, the surface of the ink receiving layer 20 on the anionic layer 21 side is in contact with the support 10.

[Support]
As the support 10 in the ink jet recording sheet 1, either a gas permeable support or a gas impermeable support can be used, but a gas impermeable support is preferable. This is because when a non-air-permeable support is used, it is possible to suppress a so-called cockling defect that the recording sheet stretches and undulates due to the influence of a solvent such as moisture contained in the ink. However, in the case of a non-permeable support, the ink cannot be absorbed by the support 10, so that the ink receiving layer 20 needs to have a sufficient absorbing power.
Further, the support 10 may be transparent or opaque.

  Specific supports 10 include films of cellophane, polyethylene, polypropylene, soft polyvinyl chloride, hard polyvinyl chloride, polyester, etc., fine paper, art paper, coated paper, cast coated paper, foil paper, kraft paper Examples include papers such as polyolefin resin-coated paper, impregnated paper, vapor-deposited paper, and water-soluble paper, and sheets such as metal foil and synthetic paper. Coated paper, baryta paper, photographic paper base paper, synthetic paper, and polyolefin resin-coated paper are preferred. Among them, synthetic paper and polyethylene resin-coated paper are more preferable, and in particular, the support 10 made of polyethylene resin-coated paper kneaded with titanium oxide, so-called RC paper, has a finished appearance equivalent to that of photographic printing paper. Preferably used. Moreover, when RC paper is used as the support 10, the effects of the present invention are particularly exerted.

  In the polyethylene resin-coated paper, the thickness of the polyethylene layer is preferably 3 to 50 μm, and more preferably 5 to 30 μm. When the thickness of the polyethylene layer is less than 3 μm, defects such as holes in the polyethylene resin are likely to increase during resin coating, the thickness is often difficult to control, and smoothness is difficult to obtain. On the other hand, if it exceeds 50 μm, the resulting effect is small and uneconomical for the increase in cost.

  The support 10 can be subjected to known anchor coating treatment, corona treatment, or the like, if necessary. Further, a gelling agent may be coated on the surface on which the ink receiving layer 20 is formed. Here, the gelling agent crosslinks the resin component contained in the ink receiving layer 20. Specifically, as the gelling agent when the binder in the ink receiving layer 20 is polyvinyl alcohol or various modified polyvinyl alcohols, an aldehyde-based crosslinking agent such as glyoxal, an epoxy-based crosslinking agent such as ethylene glycol diglycidyl ether, Examples thereof include vinyl crosslinking agents such as bisvinylsulfonylmethyl ether, boron-containing compounds such as boric acid and borax, zirconium compounds, aluminum compounds, and chromium compounds. Among these, since thickening or gelation is quick, a crosslinking agent is preferable and a boron-containing compound is more preferable.

  Here, the boron-containing compound is an oxygen acid having a boron atom as a central atom and a salt thereof. Specific examples include orthoboric acid, metaboric acid, hypoboric acid, tetraboric acid, pentaboric acid, and sodium, potassium and ammonium salts thereof. Among these, orthoboric acid and disodium tetraborate are preferably used because they have an effect of appropriately thickening the coating solution.

[Ink receiving layer]
The ink receiving layer 20 has an anionic layer 21. In the present invention, the anionic layer is an anionic layer and is a layer formed by application of an anionic coating liquid.
Here, the anionic coating liquid is a coating liquid containing an anionic compound and has a negative potential when the zeta potential is measured using the coating liquid as a sample. The zeta potential of the anionic coating liquid is preferably −50 mV or more and less than 0 mV.
Examples of the anionic compound include anionic fine particles, carboxylic acid compounds, sulfonic acid compounds, phosphoric acid compounds, ester compounds, and salts thereof.

  Examples of the anionic fine particles include colloidal silica, amorphous silica, titanium oxide, barium sulfate, kaolin, clay, calcined clay, zinc oxide, aluminum hydroxide, calcium carbonate, satin white, aluminum silicate, zeolite (natural zeolite, synthesis) Zeolite), sepiolite, smectite, synthetic smectite, magnesium silicate, magnesium carbonate, diatomaceous earth, and hydrotalcite. The average secondary particle diameter of the anionic fine particles is preferably 0.7 μm or less from the viewpoint of glossiness.

Examples of the carboxylic acid compounds include aliphatic saturation such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, peric acid, azelaic acid, sebacic acid, malic acid, tartaric acid, and cyclopropanedicarboxylic acid. Aliphatic unsaturated dicarboxylic acids such as dicarboxylic acid, maleic acid, fumaric acid, citraconic acid and itaconic acid, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, carboxyphenylacetic acid, carboxyphenylpropionic acid and phenylenediacetic acid And tricarboxylic or higher polycarboxylic acids such as tricarballylic acid and trimellitic acid.
Examples of the carboxylic acid compound include acrylic acid homopolymer, acrylic acid-maleic acid copolymer, α-hydroxyacrylic acid homopolymer, C5 olefin-maleic acid copolymer, isobutylene-maleic acid copolymer, and the like. These alkali metal salts, ammonium salts, and amine salts can also be used.

Examples of the sulfonic acid compound include alkylbenzene sulfonic acid such as diphenyl ether sulfonic acid and n-butylbenzene sulfonic acid, alkyl sulfonic acid, n-amyl benzene sulfonic acid, n-octyl benzene sulfonic acid, n-dodecyl benzene sulfonic acid, n-octadecylbenzenesulfonic acid, n-dibutylbenzenesulfonic acid, alkylnaphthalenesulfonic acid, iso-propylnaphthalenesulfonic acid, dodecylnaphthalenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, quinacridonesulfonic acids, etc. It is done. In addition, metal salts such as sodium salts and potassium salts thereof, ammonium salts thereof and the like can be mentioned.
As the sulfonic acid compound, a styrene sulfonic acid polymer and an alkali metal salt, ammonium salt, or amine salt thereof can be used.

  Specific examples of the ester compound include alkyl sulfate ester, polyoxyalkylene alkyl sulfate ester, polyoxyalkylene alkyl phenyl ether sulfate, tristyrenated phenol sulfate ester, polyoxyalkylene distyrenated phenol sulfate ester, vinyl acetate, acrylic acid Methyl, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, benzyl acrylate, N, N-dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid Propyl, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, N, N-dimethylaminoethyl methacrylate, methyl fumarate, ethyl fumarate , Propyl fumarate, butyl fumarate, dimethyl fumarate, diethyl fumarate, dipropyl fumarate, dibutyl fumarate, methyl maleate, ethyl maleate, propyl maleate, butyl maleate, dimethyl maleate, diethyl maleate, malein Examples include dipropyl acid, dibutyl maleate, alkyl phosphate ester, and polyoxyalkylene phosphate ester. In addition, metal salts such as sodium salts and potassium salts thereof, ammonium salts thereof and the like can be mentioned.

The anionic layer 21 in the present embodiment preferably contains anionic fine particles among the above anionic compounds.
Further, the anionic layer 21 in the present embodiment includes a nonionic nonionic resin (B) that functions as a binder.

Here, examples of the nonionic nonionic resin (B) include water-soluble resins and / or water-dispersible resins.
Here, examples of the water-soluble resin include polyvinyl alcohol, silyl-modified polyvinyl alcohol, polyvinyl acetal, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, casein, soy protein, synthetic proteins, starch, polypropylene oxide, polyethylene glycol, polyvinyl ether, and polyvinyl. Examples include acrylamide and polyvinyl pyrrolidone.
Examples of water-dispersible resins include vinyl copolymers such as styrene-butadiene copolymer, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, acrylic polymer latex, and styrene-vinyl acetate copolymer. Examples include coalesced latex.

The ink receiving layer 20 has a cationic layer 22. In the present invention, the cationic layer is a layer having a cationic property, and is a layer formed by application of a cationic coating solution.
Here, the cationic coating liquid is a coating liquid containing a cationic compound and has a positive potential when the zeta potential is measured using the coating liquid as a sample. The zeta potential of the cationic coating liquid is preferably more than 0 mV and not more than +60 mV. Examples of the cationic compound include cationic fine particles, cationic resins, cationic surfactants, water-soluble metal compounds, and the like. It is done.

  Examples of the cationic fine particles include alumina, alumina hydrate, and aluminosilicate. Further, as the cationic fine particles, cationized silica obtained by treating the surface of anionic fine particles such as silica and colloidal silica with a cationic resin, a water-soluble polyvalent metal salt, a silane coupling agent, or the like can also be used.

Examples of the cationic resin include 1) polyalkylene polyamines such as polyethylene polyamine and polypropylene polyamine or derivatives thereof, 2) acrylic polymers having secondary amino groups, tertiary amino groups, and quaternary ammonium groups, 3) polyvinyl amine and polyvinyl amidine compounds, 4) dicyandiamide-formalin copolymer, 5) dicyandiamide-polyethylene amine copolymer, 6) epichlorohydrin - dimethylamine copolymers, 7) diallyldimethyl ammonium -SO ₂ double condensate, 8) diallylamine salt · SO ₂ double condensate, 9) diallyldimethyl ammonium chloride polymers, 10) diallyldimethyl ammonium chloride - acrylamide copolymers, 11) copolymers of allylamine salts, 12) dialkylamino Chill (meth) acrylate 4 Kyushiotomo polymer, 13) acrylamide-diallylamine copolymer, 14) a polymer having a 5-membered ring amidine structures, 15) such as cation-modified polyvinyl alcohol.

The cationic layer 22 in the present embodiment contains a cationic resin among the above cationic compounds.
Further, the cationic layer 22 in the present embodiment includes a nonionic nonionic resin (C) that functions as a binder. As nonionic resin (C) in the cationic layer 22, the same thing as nonionic resin (B) is mentioned.

  The cationic layer 22 may contain the anionic compound. However, the content of the anionic compound is an amount within a range in which the cationic property of the cationic coating liquid is maintained.

The ink receiving layer 20 has an intermediate layer 23. In the present invention, the intermediate layer is a nonionic layer and is a layer formed by application of a nonionic coating liquid.
Here, the nonionic coating liquid is a coating liquid containing a nonionic compound as a main component, a coating liquid having a zeta potential of approximately 0 mV, and may exhibit weak cationicity or anionicity.
Examples of nonionic compounds include nonionic fine particles and nonionic resins.
Nonionic fine particles include, for example, organic pigments, and specific examples of organic pigments include acrylic or methacrylic resins, vinyl chloride resins, vinyl acetate resins, styrene-acrylic resins, styrene-butadiene resins. , Styrene-isoprene resin, polyester, polycarbonate, silicone resin, urea resin, melamine resin, epoxy resin, phenol resin, diallyl phthalate resin, and the like.
As nonionic resin, the same thing as nonionic resin (B) is mentioned.

  The intermediate layer 23 includes nonionic fine particles and a nonionic resin (A). The nonionic resin (A) is composed of the same monomer unit as the nonionic resin (B) in the anionic layer 21 or the nonionic resin (C) in the cationic layer 22 from the viewpoint of preventing generation of aggregates. The nonionic resin (B) in the anionic layer 21 and the nonionic resin (C) in the cationic layer 22 are more preferably composed of the same monomer units.

In addition, the nonionic resin (A) in the intermediate layer 23, the nonionic resin (B) in the anionic layer 21, and the nonionic resin (C) in the cationic layer 22 are anionic fine particles at the time of manufacturing the inkjet recording sheet. It is preferable that any of them is polyvinyl alcohol having an average degree of polymerization of 3000 to 7500. If the average degree of polymerization of polyvinyl alcohol is less than 3000, the resulting ink-receiving layer tends to have insufficient water resistance, and those exceeding 7500 are practically difficult to obtain.
In the case where the nonionic resin (A) in the intermediate layer 23, the nonionic resin (B) in the anionic layer 21 and the nonionic resin (C) in the cationic layer 22 are polyvinyl alcohol, It is preferable that the average degree of polymerization of the polyvinyl alcohol in the anionic layer 21 is approximately equal to the average degree of polymerization of the polyvinyl alcohol in the anionic layer 21 or the polyvinyl alcohol in the cationic layer 22. More preferably, the average degree of polymerization of the polyvinyl alcohol in the layer 22 is substantially the same.

  For the anionic layer 21, the cationic layer 22, and the intermediate layer 23, various dispersants, surfactants, thickeners, antifoaming agents, colorants, antistatic agents, preservatives, UV absorbers are used as necessary. In addition, various auxiliary agents such as preservability improver and fluorescent brightener may be contained. However, the content of the auxiliary agent must be within a range in which anionicity is maintained in the anionic layer 21, a range in which cationicity is maintained in the cationic layer 22, and a range in which nonionicity is maintained in the intermediate layer 23. .

(Method for producing inkjet recording sheet)
In order to produce the ink jet recording sheet, an anionic coating liquid is applied on a support, and an intermediate layer forming coating liquid is applied on the coated anionic coating liquid. A cationic coating solution may be applied on the intermediate layer forming coating solution.
The anionic coating liquid in the present embodiment is a coating liquid in which anionic fine particles and a nonionic resin (B) are dispersed in water, and the cationic coating liquid is a dispersion of a cationic compound and a nonionic resin (C) in water. The coating liquid for forming an intermediate layer is a coating liquid in which nonionic fine particles and nonionic resin (A) are dispersed in water.

The application method of the anionic coating solution, the cationic coating solution, and the intermediate layer forming coating solution is not particularly limited, but it is excellent in production efficiency and can further reduce the space of the production apparatus. A method in which a coating solution, a cationic coating solution and a coating solution for forming an intermediate layer are simultaneously applied by multilayer coating is preferred. Here, the simultaneous multilayer coating is a method of forming a multilayer structure by simultaneously coating two or more coating liquids on a support.
Examples of the coating apparatus applied when performing simultaneous multilayer coating include a slide bead coater and a curtain coater.

Hereinafter, an embodiment in which an anionic coating solution, a cationic coating solution, and an intermediate layer forming coating solution are simultaneously coated on a support using a slide bead coater will be described.
FIG. 2 shows a slide bead coater that performs simultaneous multilayer coating. The slide bead coater 100 includes a backup roll 110 that winds and transfers the support 10 around a peripheral surface, and a slide head 120 that is adjacent to the backup roll 110 and has a slide surface 121 that is inclined downward toward the backup roll 110. It comprises.
The slide head 120 is provided with supply channels 122a, 122b, and 122c for supplying the anionic coating solution 21a, the intermediate layer forming coating solution 23a, and the cationic coating solution 22a to the slide surface 121, respectively. . Note that the outlet of the supply channel 122b on the slide surface 121 is higher than the outlet of the supply channel 122a and opens at a position away from the backup roll 110, and the outlet of the supply channel 122c is the supply channel 122b. Is opened at a position higher than the outlet of the backup roll 110 and away from the backup roll 110.

In the simultaneous multilayer coating using the slide bead coater 100, the support 10 is brought into contact with the lower side of the peripheral surface of the backup roll 110 that rotates the support 10. Then, the backup roll 110 is rotated, and the support 10 is conveyed while being wound from the lower side to the upper side of the peripheral surface of the backup roll 110.
Further, a predetermined amount of the anionic coating liquid 21a is supplied to the supply flow path 122a of the slide head 120 and flows out from the outlet of the supply flow path 122a to the slide surface 121. At the same time, a predetermined amount of the intermediate layer forming coating liquid 23a is supplied to the supply flow path 122b, is discharged from the outlet of the supply flow path 122b to the slide surface 121, and a predetermined amount of the cationic coating liquid 22a is supplied to the supply flow path 122c. Then, it is caused to flow out from the outlet of the supply flow path 122c to the slide surface 121. At that time, on the slide surface 121, the flow of the intermediate layer forming coating liquid 23a and the cationic coating liquid 22a are sequentially overlapped on the flow of the anionic coating liquid 21a to form a multilayer flow 20a. Then, the formed multilayer flow flows down along the slide surface 121 and contacts and adheres to the support 10 on the backup roll 110. Here, since the support body 10 is conveyed with rotation of the backup roll 110 and the position where the multi-layer flow 20a adheres continuously shifts, the multi-layer flow 20a is coated on the support body 10 in a film form. . Then, through the drying process, an inkjet recording sheet 1 (see FIG. 1) in which the anionic layer 21, the intermediate layer 23, and the cationic layer 22 are sequentially formed on the support 10 is obtained.

As in the manufacturing method using the slide bead coater 100, in the case of simultaneous multilayer coating, the viscosity of the anionic coating solution, the intermediate layer forming coating solution, and the cationic coating solution is important. Specifically, The viscosity of the anionic coating solution, the intermediate layer forming coating solution, and the cationic coating solution is preferably 10 to 120 mPa · s. Further, the viscosity of the anionic coating solution is preferably 5 mPa · s or more larger than the viscosity of the intermediate layer forming coating solution, and the viscosity of the intermediate layer forming coating solution is preferably 5 mPa · s or more larger than the viscosity of the anionic coating solution. If the viscosity is in such a range, the interface between the coating liquids is not easily disturbed, so that multilayer coating can be stably performed.
In addition, the viscosity here is a value measured at 20 ° C. with a B-type viscometer (60 ppm). Although the temperature at the time of multilayer coating is often 15 to 50 ° C., the tendency of the viscosity measured at 20 ° C. is the same as the tendency of the viscosity in the temperature range at the time of multilayer coating.

As a multilayer coating method, a so-called wet-on-wet coating method in which each coating solution is sequentially applied without being dried can be employed. That is, after coating the ionic coating liquid on the support, the intermediate layer forming coating liquid is coated on the coated ionic coating liquid without drying, and the intermediate layer forming coating liquid is applied. In addition, a method of applying another ionic coating liquid having a charge opposite to that of the ionic coating liquid can be employed.
As a coating apparatus in the wet-on-wet coating method, for example, a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a rod blade coater, a lip coater, a die coater, a curtain coater, a slide bead coater, or the like can be applied.

In the method for producing an inkjet recording sheet, since the ink absorbability is increased, the dry coating amount of the intermediate layer forming coating solution is preferably 1.5 g / m ² or less, and 0.8 g / m ^2. Or less, more preferably 0.3 g / m ² or less. In addition, the wet coating amount of the intermediate layer forming coating liquid is preferably 50 g / m ² or less, more preferably 20 g / m ² or less, because aggregation of the anionic fine particles and the cationic compound can be further prevented. Is more preferably 10 g / m ² or less.
However, when the intermediate layer forming coating solution contains nonionic fine particles, the dry coating amount is preferably 2.0 g / m ² or less, more preferably 1.5 g / m ² or less, It is particularly preferably 1.0 g / m ² or less. The wet coating amount is preferably 30 g / m ² or less, more preferably 20 g / m ² or less, and particularly preferably 10 g / m ² or less.

  In the above-described embodiment, when forming an anionic layer and a cationic layer by applying an anionic coating solution and a cationic coating solution in multiple layers, a nonion is provided between the anionic coating solution and the cationic coating solution. Since the intermediate layer forming coating liquid is interposed, contact between the anionic coating liquid and the cationic coating liquid can be avoided. Therefore, aggregation of the anionic compound in the anionic coating liquid and the cationic compound in the cationic coating liquid can be prevented. Therefore, since the anionic coating solution and the cationic coating solution can be applied in multiple layers while reducing the number of drying steps, the productivity is improved and the installation space for the manufacturing apparatus can be reduced. Therefore, the obtained inkjet recording sheet is low in cost. In addition, as a result of preventing aggregation of the anionic compound in the anionic coating liquid and the cationic compound in the cationic coating liquid, the amount of aggregate contained in the ink receiving layer can be reduced, and the quality of the ink jet recording sheet can be improved. .

In addition, this invention is not limited to embodiment mentioned above. For example, a cationic coating liquid is coated on a support, an intermediate layer forming coating liquid is coated on the coated cationic coating liquid, and an anionic property is applied on the coated intermediate layer forming coating liquid. An ink jet recording sheet may be produced by coating the coating liquid and sequentially forming a cationic layer, an intermediate layer, and an anionic layer on the support.
For example, an intermediate layer may be formed on the cationic ink receiving layer, and an anionic gloss layer may be formed on the intermediate layer. In this case, the gloss layer can contain anionic colloidal silica.
Further, for example, a cationic ink receiving layer, an intermediate layer, and an anionic ink permeable layer may be sequentially formed on a transparent support. In this case, if the ink transmission layer is transparent, it can be used as an OHP sheet, and if it is opaque, it can be used as a recording sheet viewed from the support side.

In the embodiment described above, a nonionic resin is used as the binder for the anionic layer 21 and the cationic layer 22. For example, an anionic resin is used as the binder for the anionic layer 21, and a binder is used for the cationic layer 22. A cationic resin may be used.
The ink jet recording sheet may have other layers such as a glossy layer.
Further, the present invention can be applied not only to the production of inkjet recording sheets, but also to multilayer coated sheets such as thermal transfer sheets, thermal recording materials, and printing sheets.

It is sectional drawing which shows one Embodiment of the multilayer coating sheet of this invention. It is a figure explaining one Embodiment of the manufacturing method of the multilayer coating sheet of this invention.

Explanation of symbols

1 Inkjet recording sheet (Multilayer coating sheet)
10 Support 20 Ink Receptive Layer (Coating Layer)
21 anionic layer 21a anionic coating liquid 22 cationic layer 22a cationic coating liquid 23 intermediate layer 23a intermediate layer forming coating liquid 100 slide bead coater 110 backup roll 120 slide head 121 slide surfaces 122a, 122b, 122c supply flow path

Claims (5)

In a multilayer coating sheet having a support and a coating layer formed on the support,
A multilayer coating sheet, wherein the coating layer comprises an anionic layer, a cationic layer, and a nonionic intermediate layer formed between the anionic layer and the cationic layer. A method for producing a multilayer coating sheet by coating an anionic coating solution and a cationic coating solution on a support,
An anionic coating liquid is applied onto a support, and a nonionic intermediate layer forming coating liquid is applied onto the coated anionic coating liquid, and the applied intermediate layer forming coating liquid is applied. A method for producing a multilayer coated sheet, comprising coating a cationic coating liquid on the top. A method for producing a multilayer coating sheet by applying a cationic coating liquid and an anionic coating liquid on a support,
A cationic coating solution is applied onto the support, and a nonionic intermediate layer forming coating solution is applied onto the coated cationic coating solution, and the applied intermediate layer forming coating solution is applied. A method for producing a multilayer coated sheet, comprising coating an anionic coating liquid on the top. A method of producing a multilayer coating sheet by coating an anionic coating solution and a cationic coating solution on a support,
A method for producing a multilayer coating sheet, comprising simultaneously coating an anionic coating liquid, a nonionic intermediate layer-forming coating liquid, and a cationic coating liquid on a support.   The method for producing a multilayer coated sheet according to any one of claims 2 to 4, wherein the anionic coating liquid and the cationic coating liquid contain fine particles, and the multilayer coated sheet is an inkjet recording sheet.

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