JP2010227905A - Method of preparing emulsion of fatty acid and method of producing cast-coated paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of preparing an emulsion of a fatty acid, by which the water insoluble emulsion is easily obtained with high productivity and a method of producing cast-coated paper using the emulsion obtained by the method of preparing the emulsion. <P>SOLUTION: The method of preparing the emulsion of the fatty acid includes a first step of adding a base in the fatty acid in water to obtain a basic salt aqueous solution of the fatty acid; a second step of adding an emulsifying agent to the basic salt aqueous solution of the fatty acid to obtain an emulsifying agent-containing basic salt aqueous solution; and a third step of adding an acid to the emulsifying agent-containing basic salt aqueous solution to obtain the emulsion of the fatty acid. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing an emulsion of fatty acid and a method for producing cast coated paper using the emulsion of fatty acid obtained by the method for producing emulsion.

  The ink jet recording method that forms an image by ejecting ink droplets from fine nozzles and depositing them on the surface of the recording medium has low noise during recording, easy formation of full-color images, and high speed It is widely used in terminal printers, facsimiles, plotters, form printing, and the like due to the fact that recording is possible and the recording cost is lower than other printing apparatuses.

A cast coating method is widely used for producing a recording material used in an ink jet recording method. According to the cast coating method, since the glossy surface of a drum or the like is copied onto the surface of the wet coating layer, cast coated paper having excellent glossiness can be obtained.
One of the problems in the cast coating method is the aptitude for releasing the paper dried on the cast drum from the drum, that is, the aptitude called releasability. If the releasability is inferior, the cast layer surface is damaged, and the gloss is lost or the coating layer or paper is torn, which not only affects the quality but also greatly affects the productivity. Therefore, in the cast coating method, a release agent is added to the coating layer that copies the mirror surface.

Cast coated paper used in the ink jet recording system is usually provided with a cationic coating layer for the purpose of fixing the dyes and pigments recorded and printed. In such a cast coated paper for inkjet recording, it is preferable that the cast coated layer which is the outermost layer is also a cationic coated layer. When the cast coating layer is cationic, substances that can be added to a cationic system, such as cation-modified polyethylene emulsion, stearamide, oleamide, and the like have been used.
However, these substances generally have a little release effect, and if the addition amount is large, the release property becomes good, but the ink absorbability deteriorates, and both sufficient release property and recordability are compatible. It is difficult to make it. Therefore, in order to ensure excellent releasability, it is desirable that fatty acids such as oleic acid, stearic acid, and palmitic acid, which are anionic release agents, can be easily used in a cationic coating layer. ing.
In that case, the anionic fatty acid cannot be stably dispersed in the cationic coating layer as it is, so that it is preliminarily emulsified and then mixed with other coating layer components. (Patent Document 1).

Methods for producing emulsions of water-insoluble substances such as fatty acids are roughly divided into two methods: physical methods and chemical methods.
The former physical method is a method of making fine particles by applying a strong shearing force or shear stress to a substance (for example, Patent Document 2), and the latter chemical method is a colloid protected with a surfactant or the like. This is a method of forming particles (spherical micelles) (for example, Patent Document 3).
Chemical methods include phase inversion emulsification method, D phase emulsification method, solubilization conversion method, HLB temperature emulsification method, gel emulsification method and the like.

In the phase inversion emulsification method, first, a surfactant and a small amount of water are added to the oil to be emulsified, and the mixture is vigorously stirred to form W / O type micelles, and then water is added with vigorous stirring to invert the phase. Thus, an O / W type emulsion is obtained.
In the D-phase emulsification method, when a surfactant and a polyhydric alcohol are added to water and an oil component is added while stirring vigorously, a transparent gel called D-phase is obtained. When water is further added while stirring vigorously, an O / W emulsion is obtained.
The solubilization conversion method is a method in which a surfactant and an oil are added to water, and the mixture is vigorously stirred while applying temperature to obtain a solubilized state, which is cooled to obtain an O / W type emulsion.
The HLB temperature emulsification method uses a cloud point of a nonionic surfactant, adds a nonionic surfactant having a cloud point to water and an oil, and vigorously stirs at a temperature above the cloud point to produce a W / O type. In this method, an emulsion is prepared, and then the O / W emulsion is prepared by lowering the temperature of the system below the cloud point while continuing strong stirring.
The gel emulsification method is a method in which a surfactant and an oil component that satisfy certain conditions in terms of chemical structure are added to water, stirred to make a gel, and then water is added to make a W / O type emulsion. .

JP 2003-103915 A JP 2007-277181 A JP 2004-67939 A

However, a special apparatus is required to obtain an emulsion by a physical method. In addition, the amount of energy required for manufacturing is large. In particular, a large amount of energy is required to make solid fatty acids fine particles at room temperature.
In addition, in any method for producing an emulsion by a chemical method, strong stirring is required. Therefore, the amount of energy required for manufacturing is large. In addition, bubbles are easily generated during the process of strong stirring, not only the workability is low, but also the control of manufacturing conditions is difficult.
This invention is made | formed in view of the said situation, The cast using the emulsion obtained by the manufacturing method of the fatty acid emulsion which can obtain the emulsion of a fatty acid easily and with high productivity, and this manufacturing method It is an object to provide a method for producing a coated paper.

In order to achieve the above object, the present invention employs the following configuration.
[1] A method for producing an emulsion of a water-insoluble fatty acid, the first step of adding a base to the fatty acid in water to obtain a basic salt aqueous solution of the fatty acid, and an emulsifier in the basic salt aqueous solution of the fatty acid And a second step of obtaining an emulsifier-containing basic salt aqueous solution, and a third step of adding an acid to the emulsifier-containing basic salt aqueous solution to obtain an emulsion of the fatty acid. .
[2] The method for producing an emulsion according to [1], wherein the fatty acid is a linear fatty acid having 12 to 30 carbon atoms.
[3] The emulsion production method according to [1] or [2], wherein the fatty acid is a fatty acid having a melting point of 40 to 85 ° C.
[4] The method for producing an emulsion according to any one of [1] to [3], wherein the emulsifier is nonionic.
[5] The method for producing an emulsion according to any one of [1] to [4], further comprising a fourth step of refining the fatty acid that has been made into an emulsion.
[6] A step of transferring the mirror surface of the mirror body onto the wet coating layer surface containing the fatty acid emulsion obtained by the emulsion manufacturing method according to any one of [1] to [5]. A method for producing cast coated paper characterized by the above.

  According to the emulsion production method of the present invention, an emulsion of fatty acids can be obtained easily and with high productivity. Moreover, according to the manufacturing method of the cast coated paper using the emulsion obtained by this manufacturing method, a fatty acid can be easily used as a mold release agent irrespective of whether a coating layer is cationic or anionic. Therefore, particularly when used in an ink jet recording method, sufficient releasability and recording suitability can be achieved.

<Method for producing emulsion of fatty acid>
The emulsion manufacturing method of this invention processes the fatty acid used as emulsification object in the following 1st-3rd processes. In this invention, you may perform a 4th process further as needed.

[fatty acid]
The fatty acid to be emulsified in the present invention is a water-insoluble fatty acid, and in the case of a linear saturated fatty acid, it is a fatty acid having 5 or more carbon atoms. An increase in the number of carbon atoms and an increase in the viscosity of the fatty acid is preferable because the benefits of applying the present invention are increased. In particular, when the fatty acid is a paste or solid at normal temperature, such as a linear saturated fatty acid having 12 or more carbon atoms, the benefit of applying the emulsification method of the present invention in which the fatty acid is once liquefied and processed is large. In the case of unsaturated fatty acids, even an even larger number of carbon atoms may be liquid at room temperature, but even in such a case, the emulsification method of the present invention can be used, and depending on the intended use of the emulsion, Applicable to unsaturated fatty acids.
On the other hand, if the carbon number is too large, it is difficult to form an aqueous solution in the first step. Therefore, the preferable carbon number is 30 or less. A more preferable carbon number is 24 or less.

  The function of the release agent for cast coated paper is to peel the dried cast glossy layer from the surface of a drum or the like. Specifically, it is important to form a multilayer film of a release agent on the drum surface and to separate the drum side and the paper side in the middle. In that case, if the vicinity of the hydrophilic group is too large compared to the lipophilic group part, even if the hydrophilic group of the release agent is arranged on the metal surface of the drum, the interval between the lipophilic groups is not sufficiently close, It is considered that it is difficult to form a multilayer film in which lipophilic groups and hydrophilic groups face each other alternately. When used as a release agent for cast coated paper, fatty acids are preferably used because the hydrophilic groups are compact and have moderate hydrophilicity.

Unsaturated fatty acids are considered to be difficult to arrange in a layer on the cast drum as compared to saturated fatty acids because the carbon chain contains double bonds and the molecules are bent. Accordingly, when used as a release agent for cast coated paper, linear saturated fatty acids are preferred. In the production of cast coated paper, when the release agent is melted at the temperature of the cast drum surface, the release property can be expressed well, so the melting point of the fatty acid used as the release agent is 40 to 85 ° C. It is preferable that it is 50-80 degreeC.
In the case of a linear saturated fatty acid, it is preferable that the number of carbon atoms is 12 to 22 because the melting point is in the range of 40 to 85 ° C. In the case of unsaturated fatty acids, even a larger carbon number has a low melting point and may be liquid at room temperature, but even in such a case, it is appropriately selected according to the purpose of use of the release agent and used in combination. Or can be used as a mixture.

  Fatty acids having a total carbon number of 16 to 18 are particularly preferred as a release agent for cast coating. Specifically, hexadecanoic acid (common name palmitic acid, numerical expression 16: 0), 9-hexadecenoic acid (palmitoyl acid, 16: 1), heptadecanoic acid (margaric acid, 17: 0), octadecanoic acid (stearic acid, 18: 0), cis-9-octadecenoic acid (oleic acid, 18: 1 (9)), 11 octadecenoic acid (vaccenic acid, 18: 1 (11)), cis, cis-9,12-octadecadienoic acid (Linoleic acid, 18: 2 (9,12)), 9,12,15-octadecatrienoic acid ((9,12,15) linolenic acid, 18: 3 (9,12,15)), 6,9 , 12-octadecatrienoic acid ((6,9,12) linolenic acid, 18: 3 (6,9,12,)), 9,11,13-octadecatrienoic acid ((9,11,13) linolenic Acid, 18: 3 (9, 1,13)) and the like. Of these, hexadecanoic acid (palmitic acid), octadecanoic acid (stearic acid), and cis-9-octadecenoic acid are preferred, octadecanoic acid and cis-9-octadecenoic acid are more preferred, and octadecanoic acid is most preferred.

[First step]
In the first step, a base is added to the fatty acid in water. Addition of a base produces a basic salt of a fatty acid. The basic salt of the fatty acid is an aqueous solution or a colloidal solution that is self-emulsified by forming micelles. In the present invention, the colloidal solution is referred to as an aqueous solution.
Examples of the base used in the first step include sodium hydroxide, potassium hydroxide, aqueous ammonia and the like. Ammonia water has a drawback of being vaporized by heating, but conversely has an advantage that an excessive alkali component hardly remains in the system. A particularly preferable basic substance in the present invention is aqueous ammonia.

In the first step, the concentration of the fatty acid when reacted with the base is preferably 2 to 15 parts by mass, more preferably 3 to 10 parts by mass with respect to 100 parts by mass of water. If it is 3 parts by mass or more, an emulsion can be obtained at a sufficient concentration, and if it is 10 parts by mass or less, the viscosity does not become too high and it is easy to use.
In the first step, the amount of the base to be reacted with the fatty acid is preferably 1.0 to 2.0 equivalents, and more preferably 1.1 to 1.5 equivalents. In principle, all can be converted with 1.0 equivalent, but 1.1 to 1.2 equivalent is more preferable because not only the reaction is reliable, but also the amount of acid used can be suppressed.

When the fatty acid is liquid at normal temperature, an aqueous solution of a basic salt can be obtained by putting a base and a fatty acid in water and stirring with a homogenizer or the like. When the fatty acid is solid at room temperature, an aqueous solution of a basic salt can be obtained by putting the base and the fatty acid in water and heating the mixture to the melting point or higher while stirring with a homogenizer or the like.
The first step is a step of producing an aqueous solution while neutralizing the fatty acid with a base, and the neutralized one is sequentially dissolved or micellized. Therefore, it is preferable to perform stirring to such an extent that the whole is uniform and does not foam.

[Second step]
In the second step, an emulsifier is added to the basic salt aqueous solution of fatty acid obtained in the first step to obtain an emulsifier-containing basic salt aqueous solution.
As the emulsifier to be added in the second stage, it is not appropriate to use a cationic emulsifier because the basic salt aqueous solution of the fatty acid is anionic. Therefore, a nonionic emulsifier or an anionic emulsifier is used.
In addition, when using an emulsion of fatty acids as a release agent when producing an ink jet recording body by a cast coating method, an anionic emulsifier may be used because it is finally added to a cationic system. Not appropriate. Therefore, it is preferable that the emulsifier in the case of using an emulsion of fatty acid as a release agent for the cast coating method is nonionic.

The emulsifier may be a surfactant or a water-soluble polymer having a hydrophilic part and a hydrophobic part.
Examples of nonionic surfactants include ether type and ester type surfactants. An ether type surfactant having an ethylene oxide unit as a hydrophilic group often has a cloud point. When the liquid temperature exceeds the cloud point, the ability as a surfactant is lost, but in the case of the present invention, the fatty acids are water-soluble salt aqueous solutions, and therefore precipitation and solidification occur even when the liquid temperature is lowered. However, most ether type surfactants can be used at temperatures exceeding the cloud point.
Nonionic water-soluble polymers include polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, and hydroxyethylpropyl cellulose.
Examples of the anionic surfactant include sodium dialkylsulfosuccinate, sodium alkylsulfonate, sodium alkylbenzenesulfonate, and sodium alkylphosphate.
Examples of the anionic water-soluble polymer include sodium polyacrylate and carboxymethyl cellulose.

When using an emulsion of a fatty acid as a release agent for the cast coating method, it is preferable to select a water-soluble polymer such as polyvinyl alcohol because it can increase the dye fixing power in the ink, the adhesive strength of the pigment, and the like. .
In the present invention, an optimal surfactant or water-soluble polymer for each system can be freely selected according to desired properties.

In the second step, the amount of the emulsifier to be added is appropriately adjusted depending on the type of fatty acid to be emulsified, the type of emulsifier to be used, and the like. The amount of the emulsifier is preferably small from the viewpoint of the properties as an emulsion of the fatty acid and foaming, and it is preferable not to use more than the amount necessary for the stability of the emulsion. In general, it is preferably 3 to 50%, more preferably 5 to 20% based on the amount of fatty acid.
Stirring is sufficient to make the liquid uniform, and it is preferable to keep the strength strong enough not to foam. The temperature is not particularly limited, but when a nonionic surfactant having a cloud point is used, it is preferably below the cloud point.

[Third step]
In the third step, an acid is added to the emulsifier-containing basic salt aqueous solution obtained in the second step. As the acid, an acid stronger than the fatty acid is used. The fatty acid salt contained in the aqueous solution obtained in the second step is hydrolyzed. When an acid stronger than a fatty acid is added to this and neutralized, an insoluble fatty acid is precipitated in water and an emulsion is obtained.
Specific examples of the acid added in the third step include sulfuric acid, hydrochloric acid, acetic acid, and lactic acid. Volatile acids such as hydrochloric acid, formic acid, acetic acid and the like are preferable because excess components are easily vaporized and easily get out of the system. Of these, hydrochloric acid has no off-flavor and is the most commonly preferred acid because it is a widely used acid.
The amount of acid added in the third step is preferably 1.0 to 2.0 equivalents, and 1.1 to 1.5 equivalents, per 1 equivalent of the base added in the first step. More preferably, it is 1.1-1.2 equivalent.
In principle, the total basic salt can be precipitated as a fatty acid at 1.0 equivalent, but if it is 1.1 equivalent or more, it can be more reliably converted to a fatty acid. Moreover, if it is 1.1-1.2 equivalent, while being able to convert to a fatty acid reliably, the value of final pH can be brought close to neutrality.

When an acidic substance is instilled while stirring with a homogenizer or the like, the precipitated fatty acid immediately has colloidal particles (spherical micelles) protected by the emulsifier because an emulsifier is present in the surroundings, and an emulsion is obtained. In this way, the precipitated fatty acid is successively emulsified by the emulsifier coexisting, and finally all the basic water-soluble salts are changed to fatty acid emulsions.
It is sufficient to stir slowly so that the liquid becomes uniform with a propeller mixer. Therefore, according to the present invention, an emulsion of fatty acids can be obtained without foaming.
Fatty acid emulsions obtained by slow stirring have a large particle size and may be separated into a fatty acid emulsion layer and an aqueous layer by standing, but can be easily mixed by shaking.
When a surfactant having a cloud point is used, the ability as a surfactant is lost when the liquid temperature exceeds the cloud point, so the third step is performed at a temperature below the cloud point.

[Fourth step]
Fatty acids are considered to aggregate and agglomerate when the stability decreases due to the consumption of the emulsifier after precipitation. Therefore, the 4th process which refines | miniaturizes the aggregated fatty acid is performed as needed.
For the miniaturization, it is possible to use a stirring homogenizer having a disperser or other impeller, a collision homogenizer such as a microfluidizer, or a nanomizer, a media mill such as an attritor, a sand grinder, or a ball mill.
Examples of the apparatus that causes liquid-liquid collision under high pressure to make particles in the liquid finer include Nanomizer NM2-L200 (manufactured by Yoshida Kikai Kogyo Co., Ltd.).
By performing the fourth step, an emulsion in which the particles are further refined can be obtained.

<Method for producing cast coated paper>
In general, cast processing means that the coating layer is dried by being pressed against a cast drum having a mirror surface (drum made of mirror-finished metal, etc.), a mirror-finished metal plate, a plastic sheet, a film, a glass plate, etc. It is to obtain a smooth and glossy coating layer surface by copying on the construction layer.
The method for producing cast coated paper of the present invention comprises a step of transferring the mirror surface of the mirror body onto the wet coating layer surface containing the emulsion of fatty acids obtained by the emulsion production method.
Among them, a drum casting method using a heated cast drum, a film transfer method for transferring a smooth surface of a plastic sheet or film, and the drum casting method are most preferable.

[Drum cast method]
The drum cast method tends to be excellent in surface smoothness, and is often advantageous in terms of productivity and cost. Examples of the drum casting method include a wet casting method, a rewet casting method, a gelation casting method, and a precast method.

The wet casting method is a method in which a coating liquid for the outermost coating layer is coated on a substrate, and is pressed onto a heated mirror drum while the coating liquid is in a wet state, and then dried to finish. .
When the wet cast method is adopted in the method for producing cast coated paper of the present invention, the outermost coating layer coating solution contains the emulsion of fatty acids obtained by the above-described emulsion production method.
As a result, a wet coating layer containing an emulsion of fatty acid is formed on the substrate, so that release properties from the mirror drum can be obtained when it is pressed against the mirror drum and dried.

In the rewet cast method, after the outermost coating layer coated on the substrate is once dried, it is rewetted by applying a rewet liquid to the outermost coating layer, and pressed against a heated mirror drum, It is a method of drying and finishing.
When adopting the rewet cast method in the production method of the cast coated paper of the present invention, the outermost coating layer coating liquid, the rewetting liquid, or the outermost coating layer coating liquid and the rewetting liquid Both are made to contain the emulsion of the fatty acid obtained by the said emulsion manufacturing method.
As a result, a wet coating layer containing an emulsion of fatty acid is formed on the substrate, so that release from the mirror drum can be obtained when it is pressed against the mirror drum and dried.

The gelation casting method is a method in which the outermost coating layer on the base material is gelled to form a gel-like coating layer, which is pressed onto a heated mirror drum and dried. In order to obtain a gel-like coating layer, two types of coating liquids that react with each other to form a gel are applied by wet-on-wet, after the outermost coating layer is applied, the gel is applied later. There is a method of applying an agent.
In the method for producing cast coated paper of the present invention, when the wet-on-wet gelation cast method is employed, the fatty acid emulsion obtained by the above-described emulsion production method is used as either of the two coating liquids. You may make it contain, and you may make it contain in both.
Moreover, when employ | adopting the gelation cast method of the system which apply | coats a gelatinizer afterwards, the emulsion of the fatty acid obtained by the said emulsion manufacturing method is contained in the coating liquid for outermost coating layers. .
As a result, a wet coating layer (gel coating layer) containing a fatty acid emulsion is formed on the base material, so that when it is pressed against the mirror drum and dried, it is released from the mirror drum. Is obtained

In the precast method, the coating liquid for the outermost coating layer is directly applied to a heated mirror drum, and the outermost coating layer is formed on the mirror drum after drying, and then the mirror drum is formed on the substrate. And finishing by transferring the outermost coating layer.
When the precast method is employed in the method for producing cast coated paper of the present invention, the fatty acid emulsion obtained by the above-described emulsion production method is contained in the outermost coating layer coating solution.
As a result, a wet coating layer containing an emulsion of fatty acids is directly formed on the mirror drum, so that release from the mirror drum is obtained when pressed and dried thereafter.

In each of the above drum casting methods, the temperature of the heated mirror drum is preferably 50 to 150 ° C, and more preferably 70 to 120 ° C.
Further, in each of the above drum casting methods, there is no limitation on a method for applying the coating liquid, and for example, coating is performed using a known coating apparatus such as a blade coater, a brush coater, a chamber coater, a bar coater, or a gravure coater. Can be crafted.

In each of the above drum casting methods, the mirror drum is preferably pretreated with fatty acids having a total carbon number of 16 to 18.
As fatty acids having a total carbon number of 16 to 18, hexadecanoic acid (common name palmitic acid, numerical expression 16: 0), 9-hexadecenoic acid (palmitoyl acid, 16: 1), heptadecanoic acid (margaric acid, 17: 0), Octadecanoic acid (stearic acid, 18: 0), cis-9-octadecenoic acid (oleic acid, 18: 1 (9)), 11 octadecenoic acid (vaccenic acid, 18: 1 (11)), cis, cis-9, 12-octadecadienoic acid (linoleic acid, 18: 2 (9,12)), 9,12,15-octadecatrienoic acid ((9,12,15) linolenic acid, 18: 3 (9,12,15) )), 6,9,12-octadecatrienoic acid ((6,9,12) linolenic acid, 18: 3 (6,9,12,)), 9,11,13-octadecatrienoic acid ((9 , 11, 13) Ren acid, 18: 3 (9,11,13)), and the like. Of these, hexadecanoic acid (palmitic acid), octadecanoic acid (stearic acid), and cis-9-octadecenoic acid are preferred, octadecanoic acid and cis-9-octadecenoic acid are more preferred, and octadecanoic acid is most preferred.
The reason for this is not clear, but it is presumed that saturated fatty acids having no double bond in the molecule are likely to be linear in the molecule, and therefore more likely to be densely arranged on the mirror drum surface.

As a treatment method, it is preferable not only to apply the fatty acid to the mirror drum surface but also to apply a buff. Further, when buffing, it is more effective to mix a fine powder abrasive such as ferric oxide, chromium oxide, aluminum oxide, silicon carbide, boron nitride, diatomaceous earth, calcium carbonate and the like with a fatty acid and treat it.
When surface-treating chrome-plated mirror drums, silicon carbide and boron nitride are too hard and the chrome-plated surface is highly worn, and diatomaceous earth may contain coarse particles and may be damaged. Since calcium carbonate is soft, the effect of polishing is too small. Although chromium oxide is trivalent and safe, it is preferable to use an alternative if possible. Therefore, fine powders of ferric oxide and aluminum oxide are particularly preferable. Aluminum oxide has various particle sizes and is most preferable.
The reason why the effect is great when buffing by mixing abrasive and fatty acid is not clear, but by mixing and buffing the above abrasive and fatty acid, dirt and oxide film adhering to the mirror drum surface It is speculated that at the moment when the active chromium surface appears, the fatty acid hydrophilic groups are adsorbed on the active chromium surface, and a fatty acid multilayer film is formed on the mirror drum surface.

[Film transfer method]
As a film transfer method,
(A) A coating solution for the outermost coating layer is applied onto a substrate, and a smooth film or sheet is layered and dried while the coating solution is in a wet state. The method of peeling and finishing,
(B) Applying the coating solution for the outermost coating layer on a smooth film or sheet, with the substrate surface to be bonded in a wet state to some extent, press against the substrate surface, And a method of peeling and finishing a smooth film or sheet after drying.
In any system, the fatty acid emulsion obtained by the above emulsion production method may be contained in the outermost coating layer coating solution.

<Inkjet recording material>
The ink jet recording material obtained by the method for producing cast coated paper of the present invention will be described below.
The ink jet recording material can be obtained by providing a gloss developing layer on a substrate by a casting method. The substrate is obtained by previously providing an ink receiving layer on a support.

[Support]
The support used for the ink jet recording material is not particularly limited, but it is preferable to use paper having air permeability, a resin film having air permeability, or a sheet material.
In particular, it is preferable to use paper from the viewpoints of excellent air permeability, ease of handling as a recording medium, and ease of disposal.
As the paper support, a commonly used known paper support can be used as long as the effects of the present invention are not impaired. For example, fine paper, art paper, coated paper, cast coated paper, craft Examples include paper, baryta paper, paperboard, impregnated paper, and vapor-deposited paper.
Further, acid paper, neutral paper, etc. used for general coated paper can be used as appropriate.

The paper support is mainly composed of wood pulp, and fillers, various auxiliaries and the like are added as necessary. As the wood pulp, various chemical pulps, mechanical pulps, recycled pulps and the like can be used. In particular, softwood and hardwood kraft pulp, or softwood bleached kraft pulp bleached from these kraft pulp (referred to as NBKP) and hardwood bleached kraft pulp (referred to as LBKP) are preferable.
In addition, these pulps are chlorine-free pulps that have removed the influence of chlorine in the bleaching process, such as ECF (Elemental Chlorine Free) pulp that uses chlorine compounds without using chlorine itself for pulp bleaching, and elemental chlorine for pulp bleaching. TCF (Total Chlorine Free) pulp or the like using a bleaching agent not contained at all is preferable.
These pulps can be adjusted by a beating machine to adjust paper strength, papermaking suitability, etc., and the beating degree (CSF: Canadian Standard Freeness) is not particularly limited, but 250 to 550 ml (JIS) -P8121) is preferred.

As the filler added to the paper support, for example, light calcium carbonate, heavy calcium carbonate, calcined kaolin, synthetic zeolite, silica, titanium oxide, talc and the like are preferably used. Among them, light calcium carbonate, calcined kaolin, and synthetic zeolite are preferable because they are porous and have excellent ability to absorb the solvent in the ink ejected from the ink jet printer. Among them, light calcium carbonate is a paper support with high whiteness. A body is obtained, and glossiness of the ink jet recording sheet is also increased, which is preferable.
The content (ash content) of the filler in the paper support is preferably about 1 to 20% by mass. Within this range, smoothness, air permeability, paper strength, and rigidity are balanced, and a glossy inkjet recording sheet excellent in balance of glossiness, image clarity, and rigidity is easily obtained.

Examples of the auxiliary agent added to the paper support include a sizing agent, a fixing agent, a paper strength enhancer, a cationizing agent, a yield improving agent, a dye, and a fluorescent brightening agent.
As the sizing agent, known sizing agents such as reinforced rosin and alkenyl succinic anhydride are used.
In addition, a sulfuric acid band is used as a fixing agent for the sizing agent, and starch is used as a fixing yield improving agent in combination with the sizing agent.

  The paper support may be subjected to size press processing. The purpose of the size press is to control the sizing degree, increase paper strength, smoothing, etc. The size press solution contains starches, polyvinyl alcohols, sizing agents, various pigments, etc. according to the respective public purpose. Material is used. About 1 to 300 seconds is preferable, and the Stecchito sizing degree (JIS-P8122) of the paper support is more preferably 4 to 200 seconds. If the sizing degree is less than 1 second, wrinkles may occur during coating, which may cause operational problems. If it exceeds 300 seconds, the ink absorbability may decrease, and curling or cockling after printing may occur. (Absorption wrinkles) may be remarkably unfavorable.

Although the basic weight of a paper support body is not specifically limited, About 20-400 g / m < ² > is preferable.
10-350 seconds are preferable, as for the Oken type air permeability (Japan TAPPI No. 5) of a paper support body, 10-200 seconds are more preferable, and 20-100 seconds are further more preferable.
If the air permeability is less than 10 seconds, the ink receiving layer coating liquid may permeate the paper support excessively. If it exceeds 350 seconds, the operability is improved when press-contacting the cast drum. There is a risk of lowering, which is not preferable.
The paper support is produced by a long paper machine or the like, and the thickness thereof is not particularly limited, but is appropriately selected in the range of 20 μm to 500 μm depending on the application.

(Ink receiving layer)
The ink receiving layer includes a pigment and an adhesive that holds the pigment. Furthermore, a cationic ink fixing agent is preferably contained in order to better fix the dye or pigment in the ink.

(Pigment)
As the pigment of the ink receiving layer, a fine secondary pigment having a median particle diameter of 10 nm to 3 μm is used. It is preferably selected from silica, alumina, and alumina hydrate. Among these pigments, silica is particularly preferable, and vapor phase silica having a primary particle diameter of 5 nm to 50 nm and a secondary particle diameter of 10 nm to 500 nm is more preferable.
Further, the silica is preferably silica-cationic compound aggregate particles obtained by mixing silica and a cationic compound, and this is pulverized and dispersed to be used as the aggregate fine particles having a median particle diameter of 10 nm to 2 μm. It is done. The cationic compound and silica-cationic compound aggregate particles act as an ink fixing agent, and will be described in detail in the section of the ink fixing agent.
The aggregate fine particles most preferably have a median particle diameter in the range of 30 to 500 nm. If the particle diameter is less than 10 nm, the ink absorbability may decrease. If it exceeds 2 μm, the transparency of the coating film may be inferior, the print density may be significantly decreased, and the smoothness may be impaired. In order to obtain high glossiness, it is necessary to increase the coating amount of the upper glossy expression layer. As a result, there is a concern that ink absorbability and productivity are lowered.

  The median particle size in the present specification is a median particle size based on a number-based particle size distribution measured using an apparatus based on a dynamic light scattering method. “Type particle size distribution measuring device LB-500 type (manufactured by Horiba, Ltd.)” is used, but if the measurement principle is the same, substantially the same value can be obtained even if the device model is different.

  In the ink receiving layer, a known pigment used for ordinary recording paper can be used in combination with the above-mentioned pigment having a median particle diameter of 10 nm to 3 μm within a range not impairing the effects of the present invention. These pigments include kaolin (containing clay), calcium carbonate, titanium oxide, zinc oxide, amorphous silica (containing colloidal silica), aluminum oxide, zeolite, sepiolite, smectite, synthetic smectite, magnesium silicate, magnesium carbonate, oxidation Magnesium, diatomaceous earth, styrene plastic pigment, hydrotalcite, urea resin plastic pigment, benzoguanamine plastic pigment and the like can be mentioned, and these can be used alone or in combination.

(adhesive)
As the adhesive, a water-dispersed adhesive or a water-soluble adhesive can be used alone or in combination. Examples of water-dispersed adhesives include styrene-butadiene copolymer resins, methyl methacrylate-butadiene copolymer conjugated diene resins, acrylic resins, and vinyl resins such as ethylene-vinyl acetate copolymer resins. . Among these, acrylic resins and urethane resins are particularly preferable in terms of ink absorbability and transparency of the resulting coating film. These water-dispersed adhesives may be used alone or in combination of two or more.

  Examples of water-soluble adhesives include protein such as casein, soybean protein and synthetic protein, various starches such as starch and oxidized starch, polyvinyl alcohol including modified polyvinyl alcohol such as polyvinyl alcohol, cationic polyvinyl alcohol and silyl modified polyvinyl alcohol. , Cellulose derivatives such as carboxymethyl cellulose and methyl cellulose, aqueous polyurethane resins, aqueous polyester resins, and the like.

Among these adhesives, it is preferable to use polyvinyl alcohol from the viewpoint of surface strength.
Polyvinyl alcohol used in the ink receiving layer has different properties depending on the saponification degree, and it is preferable to select the saponification degree according to the purpose.
When polyvinyl alcohol having a saponification degree of 95% or more, more preferably 98% or more is used, the strength of the coating layer is increased, foaming is less during preparation of the coating liquid, and workability during production is very good. is there.
In addition, when partially saponified polyvinyl alcohol having a saponification degree of 75 to 90% is used, the coating layer has excellent flexibility and is very effective in preventing the breakage.
These polyvinyl alcohols having different saponification degrees may be used alone or in combination depending on the purpose.

  Moreover, it is preferable that the polymerization degree of the said polyvinyl alcohol is 3500 or more, and it is especially preferable that it is 3500-5000. If the degree of polymerization is less than 3500, the strength of the ink receiving layer is weak, cracks are likely to occur, and paper dust may be generated during cutting, and if it exceeds 5000, sufficient ink absorbability is difficult to obtain. At the same time, the solution viscosity is high, and the handling surface in adjusting the coating solution may be difficult, which is not preferable.

  The amount of the adhesive of the ink receiving layer is preferably 7 to 50 parts by mass, more preferably 10 to 40 parts by mass with respect to 100 parts by mass of the pigment. If the blending amount is less than 7 parts by mass, the coating film strength may not be sufficient, and if it exceeds 50 parts by mass, the ink absorbability may be impaired.

(Ink fixing agent)
The ink fixing agent has a function of fixing a dye pigment in the ink for ink jet recording, thereby imparting water resistance to the printed image.
As the ink fixing agent, a cationic compound is used, and examples thereof include a cationic resin and a low molecular weight cationic compound (for example, a cationic surfactant).
Cationic resins are preferred from the standpoint of improving the printing density, and various known cationic resins that are generally used in inkjet recording sheets can be used.

Examples of these cationic resins include (a) polyalkylene polyamines such as polyethylene polyamine and polypropylene polyamine or derivatives thereof, and (b) an acrylic heavy group having a secondary or tertiary amino group or a quaternary ammonium group. Or acrylamide copolymers thereof, (c) polyvinylamine and polyvinylamidines, (d) dicyan-based cationic compounds represented by dicyandiamide-formalin copolymer, (e) dicyandiamide-polyethyleneamine copolymer (E) epichlorohydrin-dimethylamine copolymer, (to) diallyldimethylammonium-SO ₂ polycondensate, (thi) diallylamine salt-SO ₂ polycondensate, (li) diallyl Dimethylammonium black (U) allylamine salt copolymer, (l) dialkylaminoethyl (meth) acrylate quaternary salt copolymer, (e) acrylamide-diallylamine copolymer, (wa) 5-membered ring amidine structure. And a cationic resin.
These fixing agents are used alone or in combination of two or more.

(Silica-cationic compound aggregate fine particles)
The cationic compound aggregates with the gas phase method silica in a mixed solution with the gas phase method silica to form a silica-cationic compound aggregate. For this reason, this cationic compound is preferably used in the form of agglomerates with gas phase method silica in advance rather than being used alone.
By the way, the silica-cationic compound aggregate is pulverized and dispersed and used as a silica-cationic compound aggregate fine particle having a median particle diameter of 0.01 to 1 μm in the coating solution for the ink receiving layer.
The single-phase vapor phase silica used for forming the silica-cationic compound aggregated fine particles is a primary particle having an average particle diameter of 3 to 40 nm. The aggregated fine particles are substantially composed of primary particles. It consists of secondary particles formed by agglomeration.

An outline of a method for producing silica-cationic compound aggregate fine particles will be described.
The addition amount of the cationic compound is adjusted in the range of 1 to 30 parts by mass, preferably 5 to 20 parts by mass with respect to 100 parts by mass of the vapor phase method silica.
When a cationic compound is added to and mixed with the vapor phase silica dispersion, a thickened aggregate dispersion is obtained.
As a method of pulverizing / dispersing the silica-cationic compound aggregate particles into fine particles, a breaking down method (a method of subdividing the bulk material) that gives a strong force by mechanical means is employed.
Examples of the mechanical means include an ultrasonic wave, a high-speed rotating mill, a roller mill, a container driving medium mill, a medium stirring mill, a jet mill, a crusher, a sand grinder, a nanomizer (trade name), and a homomixer.

  The silica-cationic compound aggregated fine particles as a pigment and an ink fixing agent are used singly or in combination of two or more. By using these fine particles, transparency, surface strength, smoothness of the ink receiving layer can be obtained. As well as ink absorbency, color developability, weather resistance, water resistance, and the like.

  Further, various auxiliary agents such as a dispersant, a thickener, an antifoaming agent, an antistatic agent, and an antiseptic used in the production of general coated paper are appropriately added to the ink receiving layer. In addition, a fluorescent dye or a colorant can be added to the ink receiving layer.

In addition, a single cationic compound may be blended in the ink receiving layer in order to further improve the ink fixing property and improve the water resistance.
Examples of the cationic compound include those used in the silica-cationic compound aggregate, and among these, water-soluble resins or emulsions are preferably used.
In addition, a cationic compound, particularly a cationic resin, blended as a simple substance is often used when a role as an adhesive is also given.

(Method for forming ink receiving layer)
In order to form the ink receiving layer, for example, the coating liquid layer is reduced at the same time as the ink receiving layer coating liquid is applied or during the drying of the coating liquid layer to which the ink receiving layer coating liquid is applied. Before showing the rate of drying rate, it is effective to produce a film by thickening or crosslinking the coating liquid.
Specifically, the methods listed in the following (A) to (C) can be exemplified and can be appropriately adopted, but are not limited to these methods.

For example,
(A) It contains a hydrophilic resin that forms a hydrogel by electron beam irradiation, and immediately after coating or in the middle of drying of the coated coating layer, the coating layer is reduced at a reduced rate. Before showing, the method of thickening the coating liquid layer by irradiation with an electron beam (forms a hydrogel),
(B) The ink receiving layer is a coating liquid containing an adhesive, and immediately after coating or during the drying of the coated coating liquid layer, the coating liquid layer exhibits a reduced rate of drying. Before, a method of thickening and crosslinking the paint with a compound having crosslinkability with the adhesive,
(C) For example, a temperature-sensitive polymer compound as an adhesive (shown in the temperature region below a certain temperature (temperature-sensitive point) described in JP-A-2003-40916) exhibits hydrophilicity, and in a temperature region higher than the temperature-sensitive point. A method of increasing the viscosity of the coating liquid layer by reducing the temperature of the coating liquid layer immediately after coating,
Etc. can be exemplified.
When the coating layer is formed by the above methods (A) and (B), as the adhesive, the above-mentioned known adhesives used for inkjet recording materials can be used.

  Various known crosslinking agents and gelling agents can be used as the compound having crosslinkability with the adhesive. Examples of the compound having a crosslinking property to polyvinyl alcohol include aldehyde-based crosslinking agents such as glyoxal, epoxy-based crosslinking agents such as ethylene glycol diglycidyl ether, vinyl-based crosslinking agents such as bisvinylsulfonylmethyl ether, boric acid and borax. Examples include boron-containing compounds, glycidyl compounds, zirconium compounds, aluminum compounds, chromium compounds and the like. Among these, a boron-containing compound is particularly preferable because thickening or gelation occurs quickly.

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 salts, potassium salts, and ammonium salts thereof. Among these, orthoboric acid and disodium tetraborate are preferably used because they have an effect of appropriately thickening the paint.
Although content of a boron compound is based also on the polymerization degree of a boron compound and polyvinyl alcohol, it is preferable to contain 0.01-2.0 g / m < ² > on the single side | surface of a base material. When the content is 2.0 g / m ² or less, the crosslinking density with the hydrophilic binder does not become too high, and the coating strength can be improved. On the other hand, when the content is 0.01 g / m ² or more, the crosslinking with the hydrophilic adhesive is strengthened, the gelation of the coating is promoted, and the coating film is hardly cracked.

  For example, the ink receiving layer is preliminarily coated / impregnated with a cross-linking agent and then applied with an ink-receiving layer coating liquid, or is mixed with a cross-linking agent in the ink-receiving layer coating liquid. Alternatively, it is produced by a method of applying a cross-linking agent after applying the ink receiving layer coating liquid. Among these, it is preferable to apply a crosslinking agent in advance because thickening or gelation can be caused uniformly.

The dry solid coating amount of the ink receiving layer, but is not limited, it is preferable that generally is 2~100g / ^{m 2,} and more preferably 5 to 50 g / ^{m 2.} When the coating amount is 2 g / m ² or more, the ink absorbency in a high-definition and high-speed printer is sufficient, and when the coating amount is 50 g / m ² or less, the coating film is less likely to crack. Become.

Two or more ink receiving layers can be formed. When two or more ink receiving layers are formed as described above, the silica and the adhesive constituting each layer may be the same or different.
For example, one layer may be provided on the support as an undercoat layer that absorbs the ink solvent, and an ink dye fixing layer may be provided thereon. Alternatively, one layer may be an undercoat layer that does not allow the ink solvent to permeate the support, and an ink receiving layer may be provided thereon.
In addition, two or more types of silica and adhesive may be mixed in the same layer, or a combination thereof may be used.
Examples of the coating apparatus for forming the ink receiving layer include various coating apparatuses such as blade coaters, air knife coaters, roll coaters, bar coaters, gravure coaters, rod blade coaters, lip coaters, curtain coaters, and die coaters. It is done.

In addition, a plurality of ink receiving layers can be applied simultaneously using a slide bead coater or the like. When two or more ink receiving layers are applied, it is preferable to use a method in which the upper layer is applied onto the lower layer while the lower layer is not dried, that is, a wet-on-wet method.
Moreover, the method of performing electron beam irradiation may repeat (1) coating, electron beam irradiation, and drying, or (2) coating and applying the next layer after electron beam irradiation and drying. Well, (3) multiple layers may be applied simultaneously and irradiated with an electron beam.
Further, the coated ink receiving layer may be subjected to a smoothing process such as super calendering or brushing as necessary.

(Glossy expression layer)
The gloss developing layer is a layer comprising colloidal particles, an adhesive, and a release agent as main components and forming the outermost surface of the recording material that exhibits gloss. When the dry coating amount of the glossy layer is 0.1 to 5 g / m ² , the productivity is excellent and a clearer image can be obtained.

(Colloidal particles)
The colloidal particles in the gloss developing layer are inorganic particles or organic particles suspended and dispersed in water to form a colloidal shape. By containing the colloidal particles, uniform and high gloss can be obtained. . Examples of the colloidal particles include alumina sols such as colloidal silica, boehmite, and pseudoboehmite, colloidal alumina, cationic aluminum oxides or hydrates thereof, or colloids disclosed in Japanese Patent Publication No. 47-26959. Inorganic particles such as alumina-coated particles on the surface of silica particles, polystyrene, methyl methacrylate, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylic acid ester and methacrylic acid ester copolymer, microcapsules, urea resin And organic particles such as melamine. Preferred colloidal particles in the present invention include those obtained by dispersing and crushing colloidal silica or amorphous silica in the presence of a water-soluble compound capable of forming a protective colloid. Amorphous silica is preferably precipitated silica or vapor phase silica, which has a large primary particle size and is easy to crush rather than gel silica, which has a small primary particle size and a large secondary particle size and is difficult to crush. Vapor phase silica having a small particle size is more preferred. These colloidal particles can be used in combination of two or more.

  The colloidal particles of the glossy layer are preferably cationic colloidal particles having a function of fixing ink. Cationic colloidal particles refer to particles in which the surface of the colloidal particles is positively charged. For example, alumina sol such as boehmite and pseudoboehmite, colloidal alumina, cationic aluminum oxide, or a hydrate thereof. Examples thereof include particles obtained by coating the surface of colloidal silica particles with alumina. Further, a vapor-phase method silica in which a cationic resin or the like is selected as a water-soluble compound capable of forming a protective colloid and dispersed and pulverized in the presence thereof is also preferably used.

(adhesive)
The glossy layer contains an adhesive for the purpose of fixing colloidal particles or the like on the ink receiving layer. The adhesive is selected from the above-mentioned adhesives used for the ink receiving layer and may be used alone or in combination of two or more. However, when polyvinyl alcohol is used in the present invention, It is preferable to contain those having a degree of conversion of 98% or more. By using polyvinyl alcohol having a saponification degree of 98% or more, release from the drum is facilitated, and excellent productivity can be obtained.
The reason why the release property from the drum is improved by using polyvinyl alcohol having a saponification degree of 98% or more is not clear, but polyvinyl alcohol having a saponification degree of 98% or more is partially saponified. Since the amount of hydroxyl groups is larger than that of polyvinyl alcohol having a degree of less than 98%, the affinity with water is strong and the interaction between molecules is also strong. Therefore, when polyvinyl alcohol once dissolved in water is dried and heat-treated, polyvinyl alcohol with a saponification degree of 98% or more crystallizes and does not dissolve in water, but partially saponified polyvinyl alcohol does not crystallize and the molecules It remains flexible. This affects the difference in adhesiveness with a high-temperature drum. Polyvinyl alcohol with a saponification degree of 98% or more tends to lose its adhesive strength when the water is lost, whereas partially saponified polyvinyl alcohol has a drum. As a result, it is presumed that polyvinyl alcohol having a saponification degree of 98% or more is more easily peeled from the drum.

When the colloidal particles in the gloss developing layer are cationic or when an ink fixing agent is blended in the gloss developing layer, it is preferable to use a cationically modified adhesive.
The compounding quantity of an adhesive agent is adjusted in the range of 1-200 mass parts with respect to 100 mass parts of colloidal particles, More preferably, in the range of 10-100 mass parts.
If the blending amount of the adhesive is less than 1 part by mass, the adhesion of the glossy layer is weakened and the coating layer may be lost. Ink jet recording suitability may not be obtained, which is not preferable.

(Release agent)
As the mold release agent, an emulsion of fatty acids obtained by the above-described emulsion production method of the present invention is used.
Further, if necessary, modified polyethylene, waxes, ethylene oxide adducts of aliphatic amines or fatty acid amides, and nonionic or cationic surfactants may be used in combination. In particular, the addition of modified polyethylenes is preferable because the glossiness is improved. However, excessive addition may deteriorate the recording density and worsen scratches when feeding the printer. A preferable blending amount of the modified polyethylene is 2 to 30 parts by weight, and a particularly preferable blending amount is 3 to 15 parts by weight with respect to 100 parts by weight of the colloidal particles. Examples of the ethylene oxide adduct of aliphatic amines include N hydroxyethyl lauryl amine, polyoxyethylene lauryl amine, polyoxyethylene stearyl amine, and polyoxyethylene oleyl amine. Further, the alkyl chain may be derived from a plant (for example, palm) or an animal (for example, beef tallow), and examples thereof include polyoxyethylene coconut oil fatty acid amine and polyoxyethylene beef tallow fatty acid amine.
Examples of ethylene oxide adducts of fatty acid amides include lauric acid diethanolamide, oleic acid diethanolamide, coconut oil fatty acid monoethanolamide, beef tallow fatty acid diethanolamide, polyoxyethylene lauric acid monoethanolamide, polyoxyethylene coconut oil fatty acid amide, etc. Is exemplified.
The preferable compounding amount of these release agents is 2 to 30 parts by mass with respect to 100 parts by mass of colloidal particles, and the particularly preferable compounding amount is 3 to 15 parts by mass.

(Other additives)
In addition, the glossy layer may include an ink fixing agent, a dispersant, a crosslinking agent, a thickener (flow modifier), an antifoaming agent, a water-resistant agent (printability improver), an antistatic agent, as necessary. Various additives such as preservatives, ultraviolet absorbers, preservability improvers, fluorescent brighteners, and colorants can be appropriately added.
As the ink fixing agent, the same cationic resin as that used in the ink receiving layer is used.

  Examples of the thickener and flow modifier include (a) synthetic resin copolymers such as styrene-butadiene copolymer and methyl methacrylate-butadiene copolymer, (b) casein, (c) soybean protein, synthetic protein, etc. Proteins, (d) various starches such as starch and oxidized starch, (e) PVA, (f) cellulose derivatives such as carboxymethylcellulose and methylcellulose, (g) polycarboxylic acid, polyacrylic acid, acrylic resin emulsion, Polyamide, polyester synthetic resin polymer, (h) nonionic surfactant, and the like are appropriately used.

  Examples of the water-resistant agent and printability improver include sodium chloride, ammonium chloride, zinc chloride, magnesium chloride, sodium sulfate, potassium sulfate, ammonium sulfate, zinc sulfate, magnesium sulfate, ferrous sulfate, sodium nitrate, ammonium nitrate, first Sodium phosphate, ammonium phosphate, calcium phosphate, sodium polyphosphate, sodium hexametaphosphate, sodium formate, ammonium formate, sodium acetate, potassium acetate, sodium monochloroacetate, sodium malonate, sodium tartrate, potassium tartrate, potassium citrate, Ammonium and metal salts of inorganic and organic acids such as sodium lactate, sodium gluconate, sodium adipate, sodium dioctylsulfosuccinate, sodium aluminate, Methylamine, diethanolamine, diethylenetriamine, diisopropylamine, triethanolamine, methanolamine, ethanolamine and other amines, phosphate esters, polyoxyethylene alkylphenol ether phosphate ester salts, polyoxyethylene ether phosphate ester salts, alkylphenol ether phosphorus Phosphate esters such as acid ester salts, polyoxymethylene, alkyl ether, polyoxyethylene and aqueous ammonia, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether and adipic acid di Polyfunctional epoxy compounds such as glycidyl esters, urea-formaldehyde compounds, poly De ─ epichlorohydrin compounds, glyoxal, and the like are used as appropriate.

The above-mentioned various additives are added to the gloss developing layer coating solution in a solid content concentration of 0.05 to 10 parts, preferably 0.1 to 5 parts.
Furthermore, known white pigments such as alumina, colloidal silica, fine silica, clay and calcium carbonate can also be added to the glossy layer coating liquid as other additives.
In addition, when performing the rewetting process mentioned later, the dispersing agent, antifoaming agent, coloring agent, fluorescent dye, antistatic agent, preservative, etc. in the above additives may be added to the wetting liquid used for the rewetting process. good.

(Dry coating amount)
When a pigment having a median particle diameter of 5 μm or less, preferably 0.01 to 1 μm is contained in the ink receiving layer, the dry coating amount of the glossy layer is 0.1 to 5 g / m ² , preferably 0.3. High glossiness can be obtained with a coating amount as small as ˜2 g / m ² . When the dry coating amount is less than 0.1 g / m ² , the glossiness and print density are inferior, and when the dry coating amount is more than 5 g / m ² , the image sharpness decreases due to the deterioration of ink absorbency, and the drying load. Problems such as productivity deterioration due to an increase in the production rate occur.

Any of the above methods may be used for casting, but it is preferable to use a wet casting method in the case of an inkjet recording medium.
In this wet casting method, a uniform coating layer is easily formed, and it is easy to obtain a glossy expression layer having a high printing density and excellent gloss.

[Back layer]
In the present invention, a back surface layer is provided on the back surface, which is the other surface side of the base material not provided with the above glossy expression layer, in order to improve the texture of the photograph, the curl prevention of the ink jet recording body and the transportability. May be. Although it does not specifically limit in a back surface layer, A pigment and binder type | system | group (For example, colloidal silica and an acrylic emulsion type binder etc.), Organic emulsion type (For example, a silicon type emulsion type binder, an acrylic emulsion type binder etc.) And a hydrophilic / hydrophobic adhesive system (for example, a coating film of starch or polyvinyl alcohol), a laminate (for example, polyethylene) or the like.
Furthermore, an ink jet recording medium or other recording medium is bonded to the back surface to form a double-sided recording medium, an adhesive layer is formed on the back surface to form a label, or a magnetic card or IC card is bonded to the surface of the card. Well-known means can be applied.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
Further, “parts” and “%” in the following examples and comparative examples represent “parts by mass” and “% by mass” of solids excluding water, respectively, unless otherwise specified.

<Production of fatty acid emulsion>
[Example 1]
To 310 g of water, 13 mL of aqueous ammonia (25%) and 10 g of decanoic acid (capric acid, 10: 0, melting point 28 ° C.) were added, heated to 40 ° C. and stirred to obtain an aqueous ammonium salt solution of decanoic acid.
Next, the temperature of the ammonium salt aqueous solution is lowered to 30 ° C., 1 g of Pronon 204 (nonionic surfactant, manufactured by NOF Corporation) is added, and an aqueous solution (pH 11) in which the ammonium salt of decanoic acid and the surfactant coexist. 0.0).
While stirring this, 30 mL of dilute hydrochloric acid (10%) was added to neutralize the ammonium decanoate to obtain an emulsion. This emulsion had a pH of 2.5.
This was refined with a nanomizer NM2-L200 type (processed four times at a discharge pressure of 50 MPa) to obtain a decanoic acid emulsion having a concentration of 3%.

[Example 2]
To 312 g of water, 11 mL of aqueous ammonia (25%) and 10 g of dodecanoic acid (lauric acid, 12: 0, melting point 44 ° C.) were added, and the mixture was heated to 50 ° C. and stirred to obtain an aqueous ammonium salt solution of dodecanoic acid.
Next, the temperature of the ammonium salt aqueous solution is lowered to 30 ° C., 1 g of Pronon 204 (nonionic surfactant, manufactured by NOF Corporation) is added, and the ammonium salt of dodecanoic acid having a concentration of 3% and the surfactant coexist. An aqueous solution (pH 10.8) was obtained.
While this was stirred, 30 mL of diluted hydrochloric acid (10%) was added to neutralize the ammonium dodecanoate to obtain an emulsion. This emulsion had a pH of 2.5.
This was refined by Nanomizer NM2-L200 type (processed four times at a discharge pressure of 50 MPa) to obtain a dodecanoic acid emulsion having a concentration of 3%.

[Example 3]
To 315 g of water, 8 mL of aqueous ammonia (25%) and 10 g of cis-9-octadecenoic acid (oleic acid, 18: 1 (9), melting point 14 ° C.) were added, heated to 40 ° C., stirred, and cis-9- An aqueous ammonium salt solution of octadecenoic acid was obtained.
Next, the temperature of the ammonium salt aqueous solution is lowered to 30 ° C., 1 g of Pronon 204 (nonionic surfactant, manufactured by NOF Corporation) is added, and the ammonium salt of cis-9-octadecenoic acid with a concentration of 3% is added to the interface. An aqueous solution (pH 10.8) in which the activator coexists was obtained.
While stirring this, 30 mL of dilute hydrochloric acid (10%) was added to neutralize cis-9-octadecenoic acid ammonium salt to obtain an emulsion. This emulsion had a pH of 2.5.
This was refined with a nanomizer NM2-L200 type (treatment four times at a discharge pressure of 50 MPa) to obtain a cis-9-octadecenoic acid emulsion having a concentration of 3%.

[Example 4]
To 315 g of water, 8 mL of aqueous ammonia (25%) and 10 g of octadecanoic acid (stearic acid, 18: 0, melting point 70 ° C.) were added, heated to 75 ° C. and stirred to obtain an aqueous ammonium salt solution of octadecanoic acid.
Next, the temperature of the ammonium salt aqueous solution is lowered to 30 ° C., 1 g of Pronon 204 (nonionic surfactant, manufactured by NOF Corporation) is added, and the ammonium salt of octadecanoic acid having a concentration of 3% and the surfactant coexist. An aqueous solution (pH 10.6) was obtained.
While stirring this, 30 mL of dilute hydrochloric acid (10%) was added to neutralize ammonium octadecanoate to obtain an emulsion. This emulsion had a pH of 2.5.
This was refined by Nanomizer NM2-L200 type (processed 4 times at a discharge pressure of 50 MPa) to obtain an octadecanoic acid emulsion having a concentration of 3%.

[Example 5]
6 mL of aqueous ammonia (25%) and 10 g of docosanoic acid (behenic acid, 22: 0, melting point 82 ° C.) were added to 317 g of water, and the mixture was heated to 85 ° C. and stirred to obtain an aqueous ammonium salt solution of docosanoic acid.
Next, the temperature of the ammonium salt aqueous solution is lowered to 30 ° C., 1 g of Pronon 204 (nonionic surfactant, manufactured by NOF Corporation) is added, and the ammonium salt of docosanoic acid having a concentration of 3% and the surfactant coexist. An aqueous solution (pH 10.4) was obtained.
While stirring this, 30 mL of dilute hydrochloric acid (10%) was added to neutralize the ammonium docosanoate to obtain an emulsion. This emulsion had a pH of 2.5.
This was refined by Nanomizer NM2-L200 type (processed 4 times at a discharge pressure of 50 MPa) to obtain a docosanoic acid emulsion having a concentration of 3%.

[Example 6]
5 mL of aqueous ammonia (25%) and 10 g of tetradocosanoic acid (lignoceric acid, 24: 0, melting point 86 ° C.) were added to 318 g of water, and the mixture was heated to 90 ° C. and stirred to obtain an aqueous ammonium salt solution of tetradocosanoic acid.
Next, the temperature of the ammonium salt aqueous solution is lowered to 30 ° C., 1 g of Pronon 204 (nonionic surfactant, manufactured by NOF Corporation) is added, and the ammonium salt of tetradocosanoic acid with a concentration of 3% and the surfactant coexist. An aqueous solution (pH 10.4) was obtained.
While stirring this, 30 mL of dilute hydrochloric acid (10%) was added to neutralize the ammonium tetradocosanoate to obtain an emulsion. This emulsion had a pH of 2.5.
This was refined by Nanomizer NM2-L200 type (processed 4 times at a discharge pressure of 50 MPa) to obtain a tetradocosanoic acid emulsion having a concentration of 3%.

[Example 7]
An emulsion was obtained in the same manner as in Example 4 except that 3 g of a 10% aqueous solution of PVA117 (fully saponified polyvinyl alcohol, manufactured by Kuraray Co., Ltd.) was added instead of 1 g of Pronon 204. This emulsion had a pH of 2.5.
This was refined by Nanomizer NM2-L200 type (processed 4 times at a discharge pressure of 50 MPa) to obtain an octadecanoic acid emulsion having a concentration of 3%.

[Example 8]
An octadecanoic acid emulsion was obtained in the same manner as in Example 4 except that 3 g of a 10% aqueous solution of PVAR-1130 (silyl-modified polyvinyl alcohol, manufactured by Kuraray Co., Ltd.) was added instead of 1 g of Pronon 204. This emulsion had a pH of 2.5.

[Example 9]
An octadecanoic acid emulsion was obtained in the same manner as in Example 4 except that the treatment with Nanomizer NM2-L200 was not performed.

[Comparative Example 1]
10 g of octadecanoic acid (stearic acid, 18: 0, melting point 70 ° C.) was added to 325 g of water, and the mixture was heated to 75 ° C. and stirred to disperse octadecanoic acid.
Next, the temperature of the aqueous dispersion of octadecanoic acid is lowered to 30 ° C., 1 g of Pronon 204 (nonionic surfactant, manufactured by NOF Corporation) is added, and the dispersion of octadecanoic acid with a concentration of 3% and the surface activity are added. An aqueous solution coexisting with the agent was tried. However, when the temperature was lowered, octadecanoic acid aggregated, and an emulsion of octadecanoic acid could not be obtained.

[Comparative Example 2]
To 315 g of water, 8 mL of aqueous ammonia (25%) and 10 g of octadecanoic acid (stearic acid, 18: 0, melting point 70 ° C.) were added, heated to 75 ° C. and stirred to obtain an aqueous ammonium salt solution of octadecanoic acid.
Next, the temperature of the ammonium salt aqueous solution was lowered to 30 ° C. without adding Pronon 204 (nonionic surfactant, manufactured by NOF Corporation).
While stirring this, 30 mL of dilute hydrochloric acid (10%) was added to neutralize the octadecanoic acid ammonium salt to obtain an octadecanoic acid emulsion. However, the precipitated octadecanoic acid aggregated and an emulsion could not be obtained. There wasn't.

[Evaluation of emulsified state]
The emulsified states of Examples and Comparative Examples were evaluated according to the following criteria. The results are shown in Table 1.
3: A uniform emulsion was formed, and separation of the aqueous layer and the emulsion layer was not observed even after standing for one day.
2: It becomes a uniform emulsion, but when left for a day, separation of the aqueous layer and the emulsion layer is observed, and when stirred, it returns to a uniform emulsion.
1: An emulsion could not be obtained.

[Number average particle size]
About the emulsion of Example 4 and Example 9, the number average particle diameter was measured with the light-scattering type particle diameter measuring apparatus (SALD-2200 type, Shimadzu Corp. make). The results are shown in Table 1.

As shown in Table 1, emulsions were obtained in all examples.
Moreover, it has confirmed that the stability of an emulsion became high by performing the 4th process for refinement | miniaturization.
On the other hand, in Comparative Example 1 in which the first step of making an ammonium salt was omitted and in Comparative Example 2 in which the second step of adding an emulsifier was omitted, an emulsion was not obtained.

<Addition of fatty acid emulsion to ink jet recording body>
[Preparation of paper support]
100 parts by weight of wood pulp (LBKP; freeness 400 ml CSF), 5 parts by weight of calcined kaolin (trade name: Ancilex), 0.05 parts by weight of a commercially available sizing agent, 1.5 parts by weight of a sulfuric acid band, 0. Using a papermaking material consisting of 5 parts by mass and 0.75 parts by mass of starch, a paper support having a basis weight of 180 g / m ² was produced with a long net paper machine.

[Preparation of ink receiving layer coating solution X]
0.5 parts of dispersant (trade name: Aron SD-10, manufactured by Toagosei Co., Ltd.), 0.05 parts of antifoaming agent (trade name: Nopco 1407K, manufactured by San Nopco Co., Ltd.), cationic 10 parts of resin (trade name: Himax SC700M, manufactured by Hymo Co., Ltd.) is added, and further 100 parts of amorphous silica having an average primary particle diameter of 7 μm (trade name: Silojet P407, manufactured by Grace Japan Co., Ltd.) is added.・ Dispersed.
10 parts of modified PVA heated and dissolved (trade name: PVA R-1130, manufactured by Kuraray Co., Ltd.) was added thereto, and 2 fluorescent dyes (trade name: Whiteex BP-S, manufactured by Sumitomo Chemical Co., Ltd.) were added. Part, 0.1 part of purple dye (Daiichi Seika Co., Ltd., trade name: DC-Violet XRN), 0.05 part of blue dye (Daiichi Seika Co., Ltd., trade name: DC-Blue XB) The ink receiving layer coating solution X having a solid content concentration of 20% was prepared.

[Preparation of cationic silica fine particles]
Gas phase method silica having a median particle size of 1.0 μm (trade name: Aerosil A300, average primary particle size of about 8 nm, manufactured by Nippon Aerosil Co., Ltd.) is dispersed with a homomixer, and then the median particle size reaches 50 nm. The mixture was pulverized and dispersed with a high-speed collision type homogenizer to prepare an aqueous dispersion of 10% by mass silica.
10 parts by mass of a cationic compound having a 5-membered ring amidine structure (product name: Himax SC700M, molecular weight 300,000) having a 5-membered ring amidine structure was added to 100 parts by mass of the 10% by mass aqueous dispersion, and high-speed flow collision A 10% by mass aqueous dispersion of a silica-cationic compound having a median particle size of 0.10 μm was further dispersed with a type homogenizer.

[Preparation of ink receiving layer coating liquid Y]
To 100 parts of the above-mentioned cationic silica fine particles, PVA (manufactured by Kuraray Co., Ltd., trade name: PVA-145, polymerization degree 4500, saponification degree 99%) 10 parts, an antifoaming agent (San Nopco Co., Ltd.), (Product name: SN deformer 777) 0.1 part was mixed and stirred to prepare an ink receiving layer coating liquid Y having a solid content concentration of 12%.

[Preparation of borax solution]
100 parts of borax (manufactured by Shionogi Pharmaceutical Co., Ltd., trade name: borax) and 0.05 part of a wetting agent (trade name: Leox 2160C, manufactured by Lion Corporation) are mixed and stirred in water, and the solid content concentration is 4%. A borax solution was prepared.

[Preparation of glossy layer coating solution stock solution]
Colloidal silica in water as colloidal particles (manufactured by Nissan Chemical Co., Ltd., trade name: Snowtex AK-L, average particle size: 45 nm, primary particles) 100 parts, fully saponified polyvinyl alcohol (Kuraray Co., Ltd.) as an adhesive Product name: PVA124, saponification degree = 98%) 10 parts, acrylic resin (product name: Cybinol E67), 5 parts, cationic resin as dye fixing agent (Himo Co., Ltd.) The product is mixed with a composition solution containing 10 parts of product name: Himax SC700M, and further 5 parts of gelatin (made by Nitta Gelatin Co., Ltd., trade name: G-0667K), polyoxyethylene laurylamine (Nippon Oils and Fats ( Product name: Naimine L-207, ethylene oxide unit = 7) 5 parts, polyoxyalkylene alkyl ether (Lion Corporation) , Trade name: Rheox 2008C) 5 parts were added and mixed, to prepare a coating stock solution for a solid concentration of 15% glossy layer.

[Mirror drum processing]
A buff material mixed with 30% n-octadecanoic acid and 70% aluminum oxide fine powder (average particle size 1 μm) is thinly applied to the surface of a cast drum (surface material chrome plating) with a surface temperature of 95 ° C. A buffing treatment was performed by polishing.

[Examples 10 to 16]
After coating and drying the ink receiving layer coating liquid X on one surface side of the produced paper support so that the coating amount after drying is 8 g / m ² , coating after drying the borax liquid Coating and drying were performed so that the amount was 1 g / m ² . On this surface, the ink receiving layer coating liquid Y was applied and dried so that the weight after drying was 8 g / m ² .
Further, 10 parts of the fatty acid emulsion (see Table 2) prepared in Examples 1 to 9 were separated from the glossy layer coating liquid stock solution on the layer obtained by the ink receiving layer coating liquid Y. A coating liquid for glossy layer having a solid content concentration of 6% obtained by adding and mixing as a mold was applied (dry coating amount is 1 g / m ² ).
After applying this glossy layer coating liquid, it was immediately brought into pressure contact with a mirror drum having a surface temperature of 95 ° C. that was previously buffed.
Six seconds after the press contact, it was peeled off from the mirror drum, and ink jet recording materials of Examples 10 to 16 were obtained.

[Evaluation of releasability]
Six seconds after the press contact, when the ink jet recording body was peeled off from the mirror drum, whether or not the coating layer of the ink jet recording body remained on the mirror drum surface was evaluated according to the following criteria. The results are shown in Table 2.
5: There is no residue on the drum surface.
4: There is almost no residue on the drum surface.
3: Residual on the drum surface is somewhat visible but can be produced normally.
2: A lot of residue is observed on the drum surface, and a partial omission of the coating layer of the recording medium can be visually recognized.
1: The coating layer adheres to the drum surface, and the coating layer of the recording medium is missing.

[Evaluation of ink absorption (printing spots)]
A solid ink was printed on the ink jet recording materials of Examples 10 to 16 using a CANON ink jet printer (trademark: iP-4500) with the glossy paper and the clean mode.
It was visually observed whether or not there were spots in the solid print image and evaluated in the following three stages.
Print spots are a phenomenon that occurs when the ink that has been struck first is not completely absorbed by the coating layer of the ink jet recording body, and the next ink comes and overlaps the surface, and the ink absorption speed is slow. Then, it will appear prominently. The results are shown in Table 2.
5: No print spots are seen.
4: Print spots are slightly seen, but at a level where there is no practical problem.
3: Slightly large print spots, but at a level that is not a problem for practical use.
2: Level with many printed spots and problematic in practical use.
1: There are so many printed spots that it is not practical.

[Image clarity (print density)]
A black ink was printed on the ink jet recording materials of Examples 10 to 16 using a CANON ink jet printer (trademark: iP-4500), assuming that the print mode was glossy paper, clean mode, and no matching.
The solid print color density was measured with a Macbeth reflection densitometer (model: Gretag Macbeth RD-19, manufactured by Macbeth). The results are shown in Table 2.

As apparent from Table 2, in Examples 11 to 14 and 16, high releasability was obtained, whereas in Examples 10 and 15, the releasability was inferior. From this, it turned out that the emulsion of a C12-C22 fatty acid is preferable in order to use as a mold release agent.
In Examples 10 to 15, high ink absorbability and image sharpness were obtained, whereas in Example 16, these evaluations were inferior. From this, in order to use as a mold release agent of an inkjet recording body, it turned out that it is preferable to perform the 4th process and to use the refined | miniaturized emulsion.

  The emulsion of fatty acids obtained by the present invention can be used as a release agent in the production of cast coated paper such as ink jet recording media. It can also be used as a release agent for lightly peelable adhesive tapes or as a component of wax.

Claims (6)

A method for producing an emulsion of a water-insoluble fatty acid,
Adding a base to the fatty acid in water to obtain a basic salt aqueous solution of the fatty acid;
A second step of adding an emulsifier to the fatty acid basic salt aqueous solution to obtain an emulsifier-containing basic salt aqueous solution;
An emulsion production method comprising a third step of adding an acid to the emulsifier-containing basic salt aqueous solution to obtain an emulsion of the fatty acid.   The method for producing an emulsion according to claim 1, wherein the fatty acid is a linear fatty acid having 12 to 30 carbon atoms.   The emulsion production method according to claim 1 or 2, wherein the fatty acid is a fatty acid having a melting point of 40 to 85 ° C.   The method for producing an emulsion according to any one of claims 1 to 3, wherein the emulsifier is nonionic.   Furthermore, the emulsion manufacturing method in any one of Claims 1-4 provided with the 4th process which refines | miniaturizes the fatty acid made into the emulsion.   A cast comprising a step of transferring a mirror surface of a mirror body to a wet coating layer surface containing an emulsion of a fatty acid obtained by the method for producing an emulsion according to any one of claims 1 to 5. Manufacturing method of coated paper.