JP2011101988A - Recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording medium which keeps the excellent ink absorbing properties of an ink receiving layer, has excellent surface glossiness and color developing properties, suppresses the discoloration and color fading of an image caused by acidic gas (especially ozone) in the atmosphere, and has excellent ozone resistance. <P>SOLUTION: The recording medium having at least one layer of ink receiving layer on a substrate, is characterized in that there exists a partial film comprising a cationization poly-addition reaction product on the outermost surface, wherein the cationization poly-addition reaction product is a compound formed by cationizing at least part of amino groups of the poly-addition reaction product of at least respective one kind of compounds of (A) a sulfur-containing organic compound with two or more active hydroxide groups, (B) a polyisocyanate compound with two or more isocyanate groups, and (C) an amine compound with two or more active hydroxide groups. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a recording medium such as an inkjet recording medium.

  In order to achieve both ink absorptivity and surface gloss of an inkjet recording medium, a method of coating without applying pressure to reduce the voids of the ink receiving layer and a method of providing a silica fine particle layer on the ink receiving layer is known. (See Patent Document 1). In addition, a method of providing a layer mainly composed of a resin on an ink receiving layer is also known (see Patent Document 2).

  Various reports have been made on the addition of a sulfur-containing compound to the colorant-receiving layer in order to improve various properties such as fading prevention. An ink jet recording medium containing a thioether compound has been proposed (see Patent Document 3). Further, it has been proposed to use a thioether compound having a hydrophilic group (see Patent Document 4). Further, it has been proposed to use a polymer compound having a hydrophilic group and containing a thioether group (see Patent Document 5).

JP-A-7-76162 JP 2000-108503 A Japanese Patent Laid-Open No. 1-115677 JP 2002-86904 A JP 2004-345309 A

  However, with the method of Patent Document 1, it is possible to give the surface a certain level of gloss while maintaining high ink absorptivity, but it is not possible to obtain a glossy expression effect that is comparable to silver salt photographs. There is. In the method of Patent Document 2, since the resin may soak into the ink receiving layer in a large amount and the pores of the ink receiving layer may be filled with the resin, the absorbability may not be ensured. Further, in order to compete with silver salt photographs, excellent storage stability is also required, and the technique described in the above-mentioned patent document cannot provide an effect on the problem of excellent storage stability, particularly ozone resistance. There is a case. All the exemplified compounds described in Patent Document 3 are hydrophobic low-molecular compounds and are insoluble in water. Therefore, it may be difficult to mix in the coating liquid, and even when added as an emulsion, the surface gloss of the recording medium and the color of the printed image may be reduced. Since the exemplary compound described in Patent Document 4 is a hydrophilic low molecular weight compound, it may reduce the aging resistance under high temperature and high humidity conditions. Further, many of these compounds are low melting point compounds, and in some cases, a phenomenon occurs in which a thioether compound precipitates on the surface of a recording sheet after one week in a low temperature environment, for example, an environment of 5 ° C. or less. In addition, the method described in Patent Document 5 sometimes fails to obtain the desired surface gloss problem.

  The present invention has been made in view of the above-described actual situation. The object of the present invention is to maintain excellent ink absorbability of the ink receiving layer, to have excellent surface glossiness and color developability, and at the same time, to suppress the discoloration and fading of images due to acidic gas (especially ozone) in the atmosphere, It is to provide a recording medium having excellent ozone resistance.

  As a result of intensive studies, according to the present invention, there is provided a recording medium having at least one ink receiving layer on a support, the outermost surface having a partial film containing a cationized polyaddition reaction product, The cationized polyaddition reaction product includes a sulfur-containing organic compound (A) having two or more active hydroxyl groups, a polyisocyanate compound (B) having two or more isocyanate groups, and an amine compound having two or more active hydroxyl groups. There is provided a recording medium characterized in that it is a compound obtained by cationizing at least a part of an amino group of a polyaddition reaction product of at least one compound of (C).

  According to the present invention, excellent ink absorbability of the ink receiving layer is maintained, and it has excellent surface glossiness and color developability, and at the same time, suppresses discoloration of images due to acidic gas (especially ozone) in the atmosphere, and is excellent. A recording medium having ozone resistance is provided.

  Next, the present invention will be described in more detail with reference to preferred embodiments.

<< Recording medium >>
The recording medium of the present invention can have a support, at least one ink receiving layer on the support, and a partial film on the outermost surface. The partial coating contains a cationized polyaddition reaction product. The cationized polyaddition reaction product includes a sulfur-containing organic compound (A) having two or more active hydroxyl groups, a polyisocyanate compound (B) having two or more isocyanate groups, and an amine compound having two or more active hydroxyl groups. (C) A compound obtained by cationizing at least a part of the amino group of the polyaddition reaction product of at least one compound of each type. The ink receiving layer may be located between the support and the partial coating. The recording medium of the present invention can have an ink receiving layer and a partial coating on one side or both sides of the support. The recording medium of the present invention can be used as an inkjet recording medium.

<Support>
The support used in the recording medium of the present invention is not particularly limited, and paper such as high-quality paper, medium-quality paper, coated paper, art paper, cast-coated paper, synthetic paper, white plastic film, transparent plastic film, or semi-finished paper Transparent plastic film, resin-coated paper, etc. can be used.
In order to effectively develop the gloss of the image, a support having a high barrier property to the ink receiving layer forming coating solution is preferable, and a pigment such as titanium oxide or barium sulfate is blended to make it porous. Supported by so-called resin-coated paper in which polyethylene terephthalate, polyvinyl chloride, polycarbonate, polyimide, polyacetate, white plastic films such as polyethylene, polypropylene, polystyrene, etc., made opaque by the above, are laminated with thermoplastic resin such as polyethylene and polypropylene on the base paper It is suitable as a body.
Further, when the image quality and texture equivalent to those of a silver salt photograph are imparted as a recording medium, examples of the base paper preferably used as a support include the following. That is, a polyolefin resin-coated paper in which at least one surface on which the ink receiving layer is provided is coated with a polyolefin resin is preferable, and a polyolefin resin-coated paper in which both surfaces are coated with a polyolefin resin is more preferable. As a preferable form of the polyolefin resin-coated paper, the 10-point average roughness according to JIS-B0601 is 0.5 μm or less, and the 60-degree specular gloss according to JIS-Z-8741 is 25% or more and 75% or less.
The thickness of the resin-coated paper is not particularly limited, but is preferably 25 μm or more and 500 μm or less. If the thickness of the resin-coated paper is 25 μm or more, the rigidity of the recording medium is excellently prevented from being lowered, and there are inconveniences such as feeling and texture deterioration when the recording medium is held, and a decrease in opacity. It can be excellently prevented from occurring. Further, when the thickness of the resin-coated paper is 500 μm or less, it is possible to excellently prevent the recording medium from becoming stiff and difficult to handle, and the paper feed traveling by the printer can be smoothly performed. A more preferable range of the thickness of the resin-coated paper is 50 μm or more and 300 μm or less. The basis weight of the resin-coated paper is not particularly limited, but is preferably 25 g / m ² or more and 500 g / m ² or less.

<Ink receiving layer>
The ink receiving layer used in the present invention may be composed of one layer or may be composed of two or more layers. In all of these cases, it is preferable that each of the ink receiving layers satisfies the conditions described later. The ink receiving layer is preferably porous. The ink receiving layer used in the present invention can contain an inorganic pigment (E), at least one of a water-soluble resin and a water-dispersible resin (F), and a crosslinking agent (G). The ink receiving layer may be a solidified product of an ink receiving layer coating liquid to be described later. Further, a cationized polyaddition reaction product, which will be described later, which forms the partial coating of the present invention may be contained in the ink receiving layer within a range not impeding the effects of the present invention.
The average pore radius when the ink receiving layer is formed is preferably 5 nm or more and 20 nm or less by a nitrogen adsorption / desorption method or the like. More preferably, it is 7 nm or more and 15 nm or less. By setting the average pore radius of the entire ink receiving layer to 5 nm or more and 20 nm or less, it is possible to exhibit excellent ink absorbability and color developability. In addition, if the average pore radius of the entire ink receiving layer is 5 nm or more, it is excellent in preventing the ink absorbability from being lowered and adjusting the amount of the binder with respect to the alumina hydrate as necessary. Ink absorption can be obtained. Further, when the average pore radius of the entire ink receiving layer is 20 nm or less, it is possible to excellently prevent the haze of the ink receiving layer from being increased, and particularly good color developability can be obtained.

(Inorganic pigment (E))
The inorganic pigment (E) that can be used for forming the ink receiving layer used in the present invention is preferably fine particles that have high ink absorbability, excellent color developability, and can form high-quality images. Examples of such inorganic pigments include synthetic amorphous silica, colloidal silica, calcium carbonate, magnesium carbonate, kaolin, clay, talc, hydrotalcite, aluminum silicate, calcium silicate, magnesium silicate, synthetic amorphous silica, Colloidal silica, diatomaceous earth, alumina, alumina hydrate, colloidal alumina, aluminum hydroxide, boehmite-structured alumina hydrate, pseudoboehmite-structured alumina hydrate, lithopone, zeolite, etc. Species can be used together.
As the form of the inorganic pigment, in order to obtain a highly glossy and highly transparent ink-receiving layer, the number average secondary particle diameter is preferably 50 nm or more and 500 nm or less, more preferably 100 nm or more and 300 nm or less. When the number average secondary particle diameter of the inorganic pigment is 50 nm or more, it can be excellently prevented that the ink absorbability of the ink receiving layer to be formed is significantly lowered. In addition, when the number average secondary particle diameter is 50 nm or more, ink bleeding or beading in the ink receiving layer when printing is performed with a printer with a large ejection amount (a phenomenon in which uneven density of particles cannot be absorbed) Can be excellently prevented from occurring. On the other hand, when the number average secondary particle diameter is 500 nm or less, the transparency of the ink receiving layer to be formed is excellently prevented, and when an image is formed on the ink receiving layer, color developability and glossiness are reduced. It is possible to prevent deterioration.
Among the inorganic pigments, alumina hydrate having a boehmite structure or a pseudoboehmite structure is particularly preferably used. These inorganic pigments have particularly high ink absorbability, excellent color developability, and high-quality images. A formable ink-receiving layer can be formed.
In particular, as the inorganic pigment, alumina having a BET specific surface area of 50 m ² / g or more, and alumina hydrate having a boehmite structure or pseudoboehmite structure are preferable. More preferably, the BET specific surface area is 50 m ² / g or more and 500 m ² / g or less. When the BET specific surface area of the alumina hydrate is 50 m ² / g or more, the transparency and color developability of the ink receiving layer containing the alumina hydrate are excellently prevented, and the image appears white and dull. It is possible to excellently prevent the image from being easily changed. In addition, when the BET specific surface area of the alumina hydrate is 500 m ² / g or less, it is excellently prevented from using a large amount of acid as a peptizer to stably disperse the alumina hydrate in water. It is excellently prevented that the ink absorbability of the ink receiving layer containing a hydrate is lowered. More preferably, the BET specific surface area is 50 m ² / g or more and 250 m ² / g or less. When the alumina hydrate has a BET specific surface area of 50 m ² / g or more and 250 m ² / g or less, the ink receiving layer containing the alumina hydrate has excellent ink absorbability, beading, smoothness, and the like.
The alumina hydrate having a boehmite structure or pseudoboehmite structure preferably used in the present invention is represented by the following general formula.

Al ₂ O _3-n (OH) _2n · mH ₂ O
In the formula, n represents any of 0, 1, 2 or 3, and m represents a number of 0 to 10, preferably 0 to 5. Since mH ₂ O often represents a detachable aqueous phase that does not participate in the formation of a crystal lattice, m can take a non-integer value. Further, when this type of alumina hydrate is heated, m may be zero.
In general, an alumina hydrate crystal having a boehmite structure is a layered compound having a (020) plane forming a giant plane, and exhibits a diffraction peak peculiar to an X-ray diffraction pattern. As the boehmite structure, in addition to perfect boehmite, a structure called excess boehmite and containing excess water between layers of the (020) plane can be taken. The pseudo-boehmite X-ray diffraction pattern shows a broader diffraction peak than the complete boehmite. Since complete boehmite and pseudoboehmite are not clearly distinguishable, unless otherwise specified, both are referred to as alumina hydrate showing a boehmite structure.
Although it does not specifically limit as a manufacturing method of the said alumina hydrate, For example, it is preferable to employ | adopt methods, such as a buyer method and a light van pyrolysis method. A particularly preferable method is a method in which an acid is added to a long-chain aluminum alkoxide for hydrolysis. Moreover, the obtained alumina hydrate can control the particle | grain shape of an alumina hydrate to a specific range by adjusting the conditions of the ageing | curing | ripening process which grows a particle | grain through the process of a hydrothermal synthesis. In addition, when the aging time is appropriately set, a sol in which primary particles of alumina hydrate having a relatively uniform particle diameter are grown can be obtained. The sol obtained here can be used as a dispersion by adding an acid as a peptizer, but in order to further improve the dispersibility of alumina hydrate in water, the sol is spray-dried, etc. After pulverizing by this method, an acid can be added to form a dispersion. Moreover, conventionally known acids can be used as the acid for peptizing alumina hydrate, such as formic acid, acetic acid, propionic acid, butyric acid, glycolic acid, lactic acid, pyruvic acid, methanesulfonic acid and other organic acids, and hydrochloric acid. And inorganic acids such as nitric acid. One or more of these can be freely selected and used.

  Furthermore, examples of the alumina hydrate include commercially available Dispersal HP14 (trade name, manufactured by SASOL) and boehmite powder C01 (trade name, manufactured by Daimei Chemical Co., Ltd.). In addition, the preferable content rate of the inorganic pigment in an ink receiving layer is 30 mass% or more and 95 mass% or less.

(Water-soluble resin and water-dispersible resin (F))
In the present invention, an ink receiving layer can be formed using at least one of a water-soluble resin and a water-dispersible resin (F) together with the inorganic pigment. Examples of the water-soluble resin and water-dispersible resin used for this purpose include gelatin, casein and modified products thereof, cellulose derivatives such as methylcellulose, carboxymethylcellulose, and hydroxyethylcellulose, fully or partially saponified polyvinyl alcohol, and the like. Modified products (cation modification, anion modification, silanol modification, etc.), urea resins, melamine resins, epoxy resins, epichlorohydrin resins, polyurethane resins, polyethyleneimine resins, polyamide resins, polyvinylpyrrolidone resins, polyvinyl butyral Resin, poly (meth) acrylic acid or copolymer thereof, acrylamide resin, maleic anhydride copolymer, polyester resin, SBR latex, NBR latex, methyl methacrylate -Acrylic polymer latex such as butadiene copolymer latex and acrylic ester copolymer, vinyl polymer latex such as ethylene-vinyl acetate copolymer, and cationic groups or anionic groups on these various polymer latexes And functional group-modified polymer latexes to which is given. Among these, polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate and having a weight average polymerization degree of 300 to 5,000 is preferable. The saponification degree is preferably 70 mol% or more and less than 100 mol%. In addition, these water-soluble resins and water-dispersible resins can be used alone or in combination.
The mixing mass ratio of the inorganic pigment (E) in the ink receiving layer and the total amount of the water-soluble resin and the water-dispersible resin (F) is preferably E: F = 1: 1 to 30: 1. More preferably, E: F = 1.5: 1 to 20: 1. If the total amount of the water-soluble resin and the water-dispersible resin is within these ranges, the formed ink-receiving layer will not easily crack or fall off, and the ink absorbability will be particularly good.

(Crosslinking agent (G))
The recording medium of the present invention also includes an ink receiving layer for improving the film forming property, water resistance and strength of an ink receiving layer formed of an inorganic pigment and at least one of a water-soluble resin and a water-dispersible resin. You may add a crosslinking agent (G) in it. In general, various crosslinking agents are selected depending on the type of reactive group possessed by the polymer used. For example, in the case of polyvinyl alcohol resins, epoxy crosslinking agents, boron compounds such as boric acid, and water-soluble aluminum are used. Examples thereof include inorganic crosslinking agents such as salts and water-soluble zirconium salts.

The amount used when a boron compound is used as the crosslinking agent varies depending on the total amount of the water-soluble resin and the water-dispersible resin used as the binder, but is generally 0.1 with respect to the total amount of the water-soluble resin and the water-dispersible resin. It is good to add in the ratio of the mass% or more and 30 mass% or less. When the content of the boron compound is 0.1% by mass or more based on the total amount of the water-soluble resin and the water-dispersible resin, it is possible to excellently prevent the film-forming property from being lowered and obtain excellent water resistance. Can do. On the other hand, in the case of 30% by mass or less, it is possible to excellently prevent the change with time in the viscosity of the coating liquid from being increased, and to excellently prevent the coating stability from being lowered. The ink receiving layer can contain various additives that can be added to the ink receiving layer coating liquid described later.
Examples of the boron compound include borax, boric acid, borate, diborate, metaborate, tetraborate, and pentaborate. Of these, borax, boric acid, and borate are preferable, and boric acid is particularly preferable in that a crosslinking reaction can be promptly caused.

(Ink-receiving layer coating solution)
The ink receiving layer coating liquid that can be used in the present invention contains an inorganic pigment (E), at least one of a water-soluble resin and a water-dispersible resin (F), and a crosslinking agent (G). it can. Moreover, water can be included as a dispersion medium. The solid content concentration of the coating liquid for forming the ink receiving layer (ink receiving layer coating liquid) is not particularly limited as long as the solid content concentration has a viscosity sufficient to form the ink receiving layer on the substrate. However, it is preferably 5% by mass or more and 50% by mass or less with respect to the total mass of the ink receiving layer coating solution. More preferably, it is 15 mass% or more and 30 mass% or less. When the solid content concentration is 5% by mass or more, it is not necessary to increase the coating amount in order to increase the thickness of the ink receiving layer, and it is excellent in preventing the use of much time and energy for drying, which is uneconomical. Can be excellently prevented. Further, when the solid content concentration is 50% by mass or less, it is possible to excellently prevent the viscosity of the coating liquid from being increased, and it is possible to excellently prevent the coating property from being lowered.
Moreover, various additives can be mix | blended with the said coating liquid for ink receiving layers in the range which does not inhibit the effect of this invention. Such additives include surfactants, pigment dispersants, thickeners, antifoaming agents, ink fixing agents, dot adjusters, colorants, fluorescent brighteners, preservatives, pH adjusters, antistatic agents. And a conductive agent.
As a method for applying the prepared ink receiving layer coating liquid on the substrate, any known coating method can be applied, for example, blade coating method, air knife coating method, curtain die coating method, slot die coating, etc. Application by a coating method such as a coating method, a bar coating method, a gravure coating method, or a roll coating method is possible. After application, the ink receiving layer can be formed by drying using a drying device such as a hot air dryer, a thermal drum, or a far infrared dryer. The ink receiving layer can be formed on one side or both sides of the support. Further, for the purpose of improving the resolution and transportability of the image, smoothing processing may be performed using a device such as a calendar or cast within a range that does not hinder the effects of the present invention.
When two or more ink receiving layers are provided, the ink receiving layer can be formed by sequential application or simultaneous application of the ink receiving layer coating liquid. Moreover, the drying after application | coating may apply and dry for every layer, and may dry after application | coating of all the layers.
A preferred range for the coating amount of the ink receiving layer is 5 g / m ² or more and 50 g / m ² or less in terms of solid content. When the coating amount is 5 g / m ² or more, the formed ink receiving layer can absorb the moisture of the ink excellently, and it is possible to excellently prevent the ink from flowing and the image from bleeding. When the coating amount of the ink receiving layer is 50 g / m ² or less, it is possible to excellently prevent curling during drying, particularly reduce the occurrence of cracks, and have a remarkable effect as expected for printing performance. be able to.

<Partial film>
The partial coating used in the present invention comprises a sulfur-containing organic compound (A) having two or more active hydroxyl groups, a polyisocyanate compound (B) having two or more isocyanate groups, and an amine compound having two or more active hydroxyl groups ( A cationized polyaddition reaction product which is a compound obtained by cationizing at least a part of the amino group of the polyaddition reaction product obtained by reacting at least one compound of C). The partial film is not a film formed continuously on the entire surface of the ink receiving layer, but a film that is formed on the surface of the ink receiving layer and does not completely block the pores on the surface of the ink receiving layer. To do. In addition, the preferable content rate of the cationization polyaddition reaction product in a partial membrane | film | coat is 50 mass% or more, More preferably, it is 70 mass% or more, More preferably, it is 90 mass% or more. Moreover, the partial film may be comprised only with the cationization polyaddition reaction product.

(Sulfur-containing organic compound A)
The sulfur-containing organic compound A having two or more active hydroxyl groups, which is one of the compounds used for the synthesis of the cationized polyaddition reaction product forming the partial film used in the present invention, has two or more active hydroxyl groups. If it is a sulfur-containing organic compound which has this, it will not specifically limit. However, among these, a compound having at least one sulfide group in the molecule is preferable from the viewpoint of ozone resistance. Specific examples of the compound A used in the present invention include compounds represented by the following general formulas (1) to (6). In particular, the compound represented by the general formula (2) or the general formula (6) has a particularly high effect of suppressing discoloration of an image due to an acidic gas in the atmosphere and can be preferably used. In addition, the following compound A may be used alone or in combination of two or more with compounds B and C to synthesize a polyaddition reaction product, cationize at least a part of its amino group, and form a partial film. It is possible to synthesize addition reaction products.

(In the formula, n represents 1 or 2. R ₁ represents a methylene group, an ethylene group, or a propylene group.)

(In the formula, n represents 1 or 2. R ₂ and R ₃ each independently represents a hydrogen atom, a hydroxyl group or an alkyl group, and R ₂ and R ₃ may be the same or different. The alkyl group preferably has 1 to 5 carbon atoms.)

(Wherein n represents 0 or 1)

(Wherein n represents 1 or 2, R ₄ and R ₅ each independently represents a sulfur atom or an oxygen atom, R ₆ represents a sulfur atom or a SO ₂ group, and R ₄ and R ₅ represent (Although they may be the same or different, R ₄ and R ₆ and R ₅ and R ₆ are not the same, but are composed of different groups.)

(Wherein R ₇ and R ₈ each independently represents a hydrogen atom or an alkyl group, and R ₇ and R ₈ may be the same or different. The alkyl group has 1 to 5 carbon atoms. Preferably there is.)

(In the formula, R ₉ represents a hydroxyl group or an alkyl group. The alkyl group preferably has 1 to 5 carbon atoms.)
(Polyisocyanate Compound B)
Examples of the polyisocyanate compound B having two or more isocyanate groups used for the synthesis of a cationized polyaddition reaction product for forming a partial film used in the present invention include 2,4-tolylene diisocyanate, 2,6- Tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'- Biphenylene diisocyanate, 3,3′-dichloro-4,4′-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, 1,6-hexamethyle Diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, And 4,4′-dicyclohexylmethane diisocyanate. However, it is not limited to these, The polyisocyanate compound which has two or more other isocyanate groups can also be used. Alternatively, these polyisocyanate compounds B may be reacted alone or in combination with two or more compounds A and C, and then cationized to synthesize a cationized polyaddition reaction product that forms a partial film used in the present invention. Is possible.

(Amine compound C)
Examples of the amine compound C having two or more active hydroxyl groups used in the synthesis of the cationized polyaddition reaction product forming the partial film used in the present invention include 3 represented by the following general formula (7): Secondary amines are mentioned.

(Wherein R ₁₀ , R ₁₁ and R ₁₂ represent any one of an alkyl group, an alkanol group, an aminoalkyl group and an alkanethiol group having 1 to 6 carbon atoms, provided that R ₁₀ , R ₁₁ and At least two of R ₁₂ are alkanol groups having 1 to 6 carbon atoms.)
Specific examples of the compound C represented by the general formula (7) include, for example, N-methyl-N, N-diethanolamine, N-ethyl-N, N-diethanolamine, N-isobutyl-N, N as diol compounds. -Diethanolamine, Nt-butyl-N, N-diethanolamine, Nt-butyl-N, N-diisopropanolamine and the like, and examples of the triol compound include triethanolamine. It is possible to synthesize these cationized polyaddition reaction products that form a partial film used in the present invention by reacting these amine compounds C alone or two or more at the same time with compounds A and B and then cationizing them. is there.

(Mixing amount)
As described above, the cationized polyaddition reaction product forming the partial film used in the present invention is reacted with compound A, compound B and compound C to synthesize a polyaddition reaction product. Subsequently, the polyaddition reaction product is cationized, and a polymer containing Compound A unit, Compound B unit, and Compound C unit (at least part of the amino group in these units is cationized) in the molecule. Obtained as a compound. The amount of amine compound C used relative to all the compounds used to obtain the polyaddition reaction product (at least one of compounds A, B and C, and optionally additives such as compound D described later) is The molar ratio is preferably 5.5% or more and 18.5% or less. If the molar ratio of the amount of compound C used is 5.5% or more, it is excellently prevented that the content of hydrophilic groups is lowered, and it becomes difficult to prepare an aqueous dispersion of a cationized polyaddition reaction product. Can be excellently prevented. On the other hand, if the amount of compound C used is 18.5% or less in terms of molar ratio, the glossiness and color developability of the recording medium having a partial film containing the cationized polyaddition reaction product are excellent. Can be prevented.
If the molar ratio of the compound C used for the polyaddition reaction is within the above range, the cationized polyaddition reaction product for forming the partial film used in the present invention contains the compound C unit in the cationized polyaddition reaction product. It is possible to set it to 3 mass% or more and 80 mass% or less. If it is 80 mass% or less, it can prevent excellently causing the fall of glossiness or color developability.

  In the polyaddition reaction product, if the amount of compound C used is in the above-mentioned range, the mass of the compound A unit incorporated in the cationized polyaddition reaction product is the above-mentioned polymer compound (cationized polyaddition reaction product). ) Is preferably 10% by mass or more and 65% by mass or less. More preferably, it is 30 mass% or more and 65 mass% or less. When the proportion of the compound A unit is 10% by mass or more, an excellent ozone resistance effect can be obtained. On the other hand, when the proportion of the compound A unit is 65% by mass or less, it is excellently prevented that the content of the hydrophilic group is relatively lowered, which is inconvenient when adjusting the aqueous dispersion of the cationized polyaddition reaction product. Can be excellently prevented.

  Compound B has a function of linking compound A and compound C, and the amount used is not particularly limited. However, if the amount of compound C used is in the above-described range, the mass of compound B unit is preferably 10% by mass or more and 80% by mass or less in the resulting cationized polyaddition reaction product. More preferably, it is 30 mass% or more and 60 mass% or less. When the ratio of the compound B unit is 10% by mass or more and 80% by mass or less, an amount sufficient to exhibit the function of the unit of the compound A and the compound C can be combined.

  In addition, the mass ratio of the compound A unit, the compound B unit, and the compound C unit in the cationized polyaddition reaction product can be calculated from the charged amounts of the compounds A, B, and C, respectively.

(Method for producing polyaddition reaction product)
The method for producing the polyaddition reaction product of the compounds A to C may be a so-called one-shot method in which the compounds A to C are reacted at once to form a random polymer. Furthermore, a so-called prepolymer method is prepared by reacting compound A (or compound C) and compound B to produce a prepolymer having a terminal isocyanate group, and reacting the prepolymer with compound C (or compound A). May be used. In this case, it is preferable that the compound A (or compound C) and the compound B are reacted with the active hydroxyl group of the compound A (or compound C) at a ratio in which the isocyanate group of the compound B is rich. In any method, a chain extender such as a low molecular weight polyol or a low molecular weight diamine may be used in combination. The molecular weight of the resulting polyaddition reaction product can be adjusted by changing the amount of compounds A to C used or adding a reaction terminator such as monoalcohol or monoamine to the reaction system at an appropriate timing. .

  The weight average molecular weight of the polyaddition reaction product thus obtained is preferably 2,000 to 150,000, more preferably 2,000 to 50,000, although it depends on the reaction conditions. When the weight average molecular weight of the polyaddition reaction product is 2,000 or more, it is excellently prevented that the glossiness and printing density are lowered, and when it is 150,000 or less, it is excellently prevented that the reaction time is long, and the production cost is reduced. It can be excellently prevented from increasing.

  In the production of the polyaddition reaction product used in the present invention, a compound having two or more active hydrogen groups other than the compound A and the compound C (hereinafter referred to as “compound D”) is copolymerized as necessary. You may let them. Examples of such compound D include the following polyester polyols, polyether polyols, and polycarbonate polyols. It is also possible to synthesize these polyaddition reaction products used in the present invention alone or in combination of two or more.

Examples of the polyester polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexane. Diol, neopentyl glycol diol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol having a molecular weight of 300 to 1000, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanedimethanol, bisphenol Glycol components such as A, bisphenol S, hydrogenated bisphenol A, hydroquinone, alkylene oxide adduct,
Malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, hedecane dicarboxylic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentane Dicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bisphenoxyethane -Polyesters obtained by dehydration condensation reaction from acid components such as p, p'-dicarboxylic acid, dicarboxylic acid anhydrides or ester-forming derivatives, and cyclic ester compounds such as ε-caprolactone Polyesters obtained by ring-opening polymerization reaction, Thereof, and the like copolymerized polyesters in rabbi.

  Examples of the polyether polyol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexane. Diol, neopentyl glycol, glycerin, trimethylol ethane, trimethylol propane, sorbitol, sucrose, bisphenol A, bisphenol S, hydrogenated bisphenol A, aconitic acid, trimellitic acid, hemimellitic acid, phosphoric acid, ethylenediamine, diethylenetriamine, triisopropanol Compound having at least two active hydrogens such as amine, pyrogallol, dihydroxybenzoic acid, hydroxyphthalic acid, 1,2,3-propanetrithiol The product obtained by subjecting a product to addition polymerization by a conventional method using one or more monomers such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene as an initiator. It is done. Further, as a polyether polyol, a compound having at least two primary amino groups such as ethylenediamine and propylenediamine is used as an initiator, and ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, cyclohexyl, One obtained by subjecting one or more monomers such as silene to addition polymerization by a conventional method can also be used. Particularly preferred is polyethylene glycol.

  Examples of the polycarbonate polyol include compounds obtained by reacting glycols such as 1,4-butanediol, 1,6-hexanediol, diethylene glycol and the like with diphenyl carbonate and phosgene.

  The cationized polyaddition reaction product for forming a partial film used in the present invention desirably uses at least one of a tin-based catalyst and an amine-based catalyst in an isocyanate polyaddition reaction. Examples of the tin-based catalyst include dibutyltin dilaurate and stannous octoate. Examples of the amine-based catalyst include triethylenediamine, triethylamine, tetramethylpropanediamine, tetramethylbutanediamine, and N-methylmorpholine. It is not limited to.

  The above-mentioned isocyanate polyaddition reaction can be carried out in the absence of a solvent depending on the composition, but a hydrophilic organic solvent that does not directly participate in the isocyanate polyaddition reaction system is reacted for the purpose of controlling the reaction system or controlling the base viscosity. It is common to use as a solvent. Examples of such hydrophilic organic solvents include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, Examples thereof include organic acid esters such as methyl propionate, ethyl propionate and butyl propionate, and amines such as N, N-dimethylformamide and N-methylpyrrolidone. Moreover, it is preferable that the used hydrophilic organic solvent is finally removed by a method such as removal under reduced pressure.

(Cationized polyaddition reaction product)
At least a part of the amino groups in the cationized polyaddition reaction product forming the partial film of the present invention is cationized and can be particularly stabilized or dissolved in water. The cationized polyaddition reaction product can be obtained by cationizing the polyaddition reaction product. As a cationization method, cationization with an acid can be mentioned. Other methods include a method of cationization with a quaternizing agent such as an alkyl halide. However, a method of cationization with an acid is preferred from the viewpoint of stabilizing or dissolving the dispersion with a preferable particle size in water. The acid used here is not particularly limited, but at least one of phosphoric acid and a monovalent acid is preferable. Examples of phosphoric acid include phosphoric acid and phosphorous acid. Examples of the monovalent acid include organic acids such as formic acid, acetic acid, propionic acid, butyric acid, glycolic acid, lactic acid, pyruvic acid, and methanesulfonic acid, and inorganic acids such as hydrochloric acid and nitric acid. In addition, when a polyaddition reaction product cationized with a hydroxy acid such as glycolic acid or lactic acid is applied to the formation of a partial film on a recording medium, the non-printing portion (blank portion) is compared to the case where other acids are used. Since yellowing of is particularly suppressed, it can be used more preferably.
The cationized polyaddition reaction product that forms the partial film may be either dissolved in water or an organic solvent or finely dispersed, but more preferably dispersed in water. The average particle size of the particles is preferably 10 nm or more and 80 nm or less. When the average particle size is 10 nm or more, when the partial film is formed, it is excellently prevented that the cationized polyaddition reaction product penetrates into the ink receiving layer, and the partial film on the ink receiving layer is prevented. Can be excellently prevented from forming. On the other hand, when the average particle size is 80 nm or less, it is possible to excellently prevent the size of the partial film that does not absorb ink from being increased, and the ink absorbability can be particularly improved. The partial film size refers to the observation of an arbitrary 100 partial film on the recording surface (the surface having the ink receiving layer (and partial film)) with an electron microscope (SEM). It means the average value of the length from the end to the end. The average particle size of the aqueous dispersion of the cationized polyaddition reaction product can be measured with a laser particle size analyzer PARIII (trade name, manufactured by Otsuka Electronics Co., Ltd.).
In order to maintain the excellent properties of the ink receiving layer without hindering ink absorbability, the partial coating completely blocks the pores formed on the surface of the ink receiving layer, not a continuous homogeneous dry coating. It has a structure without so-called partial film structure. In the present invention, the coating rate of the partial coating means the area where the cationized polyaddition reaction product is coated on the entire surface of the ink receiving layer. The coating rate of the partial coating with respect to the ink receiving layer is preferably 10% or more and less than 70%, more preferably 15% or more and less than 65%. When the coating rate of the partial coating is 10% or more, it can be excellently prevented that the gloss development effect and the ozone-preserving effect are deteriorated. On the other hand, if the coating rate of the partial coating is less than 70%, the area of the pores formed on the surface of the ink receiving layer is excellently prevented from being reduced, and the ink absorption is well prevented from being reduced. . The film ratio can be obtained as an average value of the area ratio of the film portion by image processing of 10 or more observation images using an electron microscope (SEM).
The size of the partial coating is preferably 0.03 μm or more and less than 1 μm. When the size of the partial coating is 0.03 μm or more, it can be excellently prevented that the gloss development effect and the ozone-preserving effect are deteriorated. On the other hand, when the size of the partial coating is less than 1 μm, it is possible to excellently prevent the pores formed on the surface of the ink receiving layer from being blocked in a wide range. Further, when the size of the partial film is less than 1 μm, it is excellently prevented that a wide partial film that cannot absorb ink is noticeable when printing on the ink receiving layer.

(Partial coating solution)
As the coating solution for partial coating used for forming the partial coating, the reaction solution after the polyaddition reaction and cationization can be used. In addition, as described above, a dispersion liquid in which the cationized polyaddition reaction product is dispersed in water, an organic solvent, or the like can also be used as the partial film coating liquid. Various additives can be blended in the coating solution of the cationized polyaddition reaction product as the coating solution for the partial film within a range not impeding the effects of the present invention. Examples of such additives include surfactants, thickeners, antifoaming agents, dot adjusting agents, preservatives, pH adjusting agents, antistatic agents, and conductive agents.

Examples of the method for forming the partial film containing the cationized polyaddition reaction product include the following methods. The method is to apply a reaction (dispersion) liquid containing the cationized polyaddition reaction product on the ink receiving layer as a partial film coating liquid at the same time as applying the ink receiving layer coating liquid. Is a method of forming a partial film by simultaneously drying. Moreover, after providing an ink receiving layer, the method of forming the partial membrane | film | coat by overcoating the reaction liquid containing the said cationized polyaddition reaction product and drying is mentioned. When the partial coating is provided by the latter method, mixing with the ink-receiving layer coating solution is avoided, and the partial coating can be provided more efficiently. In addition, an increase in haze due to mixing of the reaction liquid containing the cationized polyaddition reaction product and the ink receiving layer coating liquid is particularly suppressed, and a decrease in color development can be avoided in particular.
In the present invention, the coating amount of the cationized polyaddition reaction product in the partial coating is 0.01 g / m ² or more to the entire surface of the ink receiving layer from the viewpoint of adjusting the coating rate of the partial coating. It is preferably 1 g / m ² or less.
If the average particle size of the cationized polyaddition reaction product (particles in the dispersion when the cationized polyaddition reaction product is used as a dispersion) is smaller than the pore size of the ink receiving layer, cationized polyaddition The penetration amount of the reaction product into the ink receiving layer is increased. For this reason, in order to form a partial film having a film rate of 10% or more and less than 70%, the coating amount must be increased. On the other hand, if the average particle size of the cationized polyaddition reaction product is larger than the pore size of the ink receiving layer, the amount of the cationized polyaddition reaction product penetrating into the ink receiving layer can be reduced. However, a partial film can be formed so as to be in the range of the film rate.
The reason why the recording medium of the present invention prevented discoloration or discoloration of an image due to acidic gas (especially ozone gas) in the atmosphere will be described below. The sulfur group contained in the cationized polyaddition reaction product has a reducibility to ozone gas, and is considered to reduce the oxidizing power of ozone gas to a dye by reducing ozone gas. In particular, in the configuration of the recording medium of the present invention, the cationized polyaddition reaction product is not contained in the ink receiving layer but is present as a partial film on the ink receiving layer. For this reason, since ozone gas is reduced before reaching the dye fixed in the ink receiving layer, the effect of ozone resistance is more than that of the constitution in which the cationized polyaddition reaction product is contained in the ink receiving layer. It is remarkable. Further, even when the cationized polyaddition reaction product is contained in the ink receiving layer, the ozone resistance is improved if the amount is considerably large, but in that case, in terms of glossiness and color developability. There are challenges.

  EXAMPLES Hereinafter, the present invention will be described with reference to examples. However, the present invention is not limited to these examples. In the following examples and comparative examples, an aqueous dispersion of a cationized polyaddition reaction product was used as a coating solution for a partial coating. In Examples and Comparative Examples, ink jet recording media were produced.

<Method for Producing Aqueous Dispersion of Cationized Polyaddition Reaction Products 1-3>
An aqueous dispersion of cationized polyaddition reaction products 1 to 3 was produced as follows.

A reaction vessel equipped with a stirrer, a thermometer and a reflux condenser was charged with 109 g of acetone as a reaction solvent, and 40.00 g of 3,6-dithia-1,8-octanediol as the compound A under stirring and the above As compound C, 6.79 g of methyldiethanolamine was added. After dissolution, the temperature was raised to 40 ° C., and 62.07 g of isophorone diisocyanate was added as Compound B. Thereafter, the temperature was raised to 50 ° C., 0.2 g of dibutyltin laurate was added as a tin-based catalyst, the temperature was further raised to 55 ° C., and the reaction was performed for 4 hours with stirring, and a polyaddition reaction product was synthesized by a one-shot method. .
After completion of the reaction, the reaction solution was cooled to room temperature, and 3.09 g of 85 mass% formic acid aqueous solution was added to cationize the polyaddition reaction product. Further, after adding water, the pressure was reduced to remove acetone, and the aqueous dispersion of the cationized polyaddition reaction product 1 having a solid concentration of 0.1% by mass was prepared by adjusting the concentration with water. Moreover, the aqueous dispersion liquid of the cationized polyaddition reaction products 2-3 in which the average particle diameter of the dispersed particles in the aqueous dispersion liquid was changed by changing the stirring conditions of the reaction solution when adding water. The amount of compound C (methyldiethanolamine) used in the synthesis of the cationized polyaddition reaction products 1 to 3 was 10.3% in molar ratio based on the total compound used to obtain the polyaddition reaction product. It is. The average particle size of the obtained aqueous dispersions of the cationized polyaddition reaction products 1 to 3 was measured with a laser particle size analyzer PARIII (trade name, manufactured by Otsuka Electronics Co., Ltd.). As a result, the average particle size of the dispersed particles of the aqueous dispersion of the cationized polyaddition reaction product 1 is 30 nm, the average particle size of the dispersed particles of the aqueous dispersion of the cationized polyaddition reaction product 2 is 10 nm, and cationized polyaddition. The average particle size of the dispersed particles of the aqueous dispersion of reaction product 3 was 100 nm.

<Method for Producing Aqueous Dispersion of Cationized Polyaddition Reaction Product 4>
An aqueous dispersion of the cationized polyaddition reaction product 4 was produced as follows.

  A reaction vessel equipped with a stirrer, a thermometer and a reflux condenser was charged with 100 g of acetone as a reaction solvent, and 40.00 g of 3,6-dithia-1,8-octanediol as the compound A under stirring and the above As compound C, 2.99 g of methyldiethanolamine was added. After dissolution, the temperature was raised to 40 ° C., and 57.08 g of isophorone diisocyanate was added as Compound B. Thereafter, the temperature was raised to 50 ° C., 0.2 g of dibutyltin laurate was added as a tin-based catalyst, the temperature was further raised to 55 ° C., and the reaction was carried out for 4 hours with stirring to synthesize a polyaddition reaction product.

  After completion of the reaction, the reaction solution was cooled to room temperature and 1.36 g of 85% by mass aqueous formic acid solution was added to cationize this polyaddition reaction product. Further, after adding water, the aqueous dispersion of the cationized polyaddition reaction product 4 having a solid content concentration of 0.1% by mass is manufactured in the same manner as the manufacturing method of the aqueous dispersion of the cationized polyaddition reaction product 1. did. The amount of compound C (methyldiethanolamine) used in the synthesis of the cationized polyaddition reaction product 4 is 5.0% in terms of molar ratio with respect to all the compounds used to obtain the polyaddition reaction product. . As a result of measuring the average particle size of the aqueous dispersion of the obtained cationized polyaddition reaction product 4 with a laser particle size analyzer PARIII (trade name, manufactured by Otsuka Electronics Co., Ltd.), the aqueous dispersion 4 was 300 nm. It was.

<Method for producing aqueous dispersion of cationized polyaddition reaction product 5>
An aqueous dispersion of the cationized polyaddition reaction product 5 was produced as follows.

  A reaction vessel equipped with a stirrer, a thermometer and a reflux condenser was charged with 94 g of acetone as a reaction solvent, and 30.00 g of 3,6-dithia-1,8-octanediol as the compound A under stirring and the above As compound C, 11.50 g of methyldiethanolamine was added. After dissolution, the temperature was raised to 40 ° C., and 52.68 g of isophorone diisocyanate was added as Compound B. Thereafter, the temperature was raised to 50 ° C., and 0.2 g of dibutyltin laurate was added as a tin-based catalyst. The temperature was further raised to 55 ° C. and the reaction was carried out for 4 hours with stirring to obtain a polyaddition reaction product.

  After completion of the reaction, the reaction solution was cooled to room temperature, and 5.24 g of 85 mass% formic acid aqueous solution was added to cationize this polyaddition reaction product. Further, after adding water, the aqueous dispersion of the cationized polyaddition reaction product 5 having a solid content concentration of 0.1% by mass was produced in the same manner as the method for producing the aqueous dispersion of the cationized polyaddition reaction product 1. did. The amount of compound C (methyldiethanolamine) used in the synthesis of the cationized polyaddition reaction product 5 is 19.4% in terms of molar ratio with respect to the total compound used to obtain the polyaddition reaction product. . As a result of measuring the average particle size of the aqueous dispersion of the obtained cationized polyaddition reaction product 5 with a laser particle size analyzer PARIII (trade name, manufactured by Otsuka Electronics Co., Ltd.), the aqueous dispersion 5 was 30 nm. It was.

<Method for producing aqueous dispersion of cationized polyaddition reaction product 6>
An aqueous dispersion of the cationized polyaddition reaction product 6 was produced as follows.

  A reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser was charged with 240 g of acetone as a reaction solvent. Under stirring, 40.00 g of 1,2-bis (2,3-dihydroxypropylthio) ethane as Compound A and 5.76 g of methyldiethanolamine as Compound C were added. After dissolution, the temperature was raised to 40 ° C., and 47.53 g of isophorone diisocyanate was added as Compound B. Thereafter, the temperature was raised to 50 ° C., and 0.1 g of dibutyltin laurate was added as a tin-based catalyst. The temperature was further raised to 55 ° C. and the reaction was carried out for 2 hours with stirring to obtain a polyaddition reaction product.

  After completion of the reaction, the reaction solution was cooled to room temperature, and 5.03 g of 35% by weight aqueous formic acid solution was added to cationize this polyaddition reaction product. Further, 380 g of water was added, and then the aqueous dispersion of the cationized polyaddition reaction product 6 having a solid content concentration of 0.1% by mass was prepared in the same manner as in the method for producing the aqueous dispersion of the cationized polyaddition reaction product 1. Manufactured. The amount of compound C (methyldiethanolamine) used in the synthesis of the cationized polyaddition reaction product 6 is 11.3% in molar ratio with respect to all the compounds used to obtain the polyaddition reaction product. . As a result of measuring the average particle size of the aqueous dispersion of the obtained cationized polyaddition reaction product 6 with a laser particle size analyzer PARIII (trade name, manufactured by Otsuka Electronics Co., Ltd.), the aqueous dispersion 6 was 30 nm. It was.

<Method for Producing Aqueous Dispersion of Cationized Polyaddition Reaction Product 7>
An aqueous dispersion of the cationized polyaddition reaction product 7 was produced as follows.

  A reaction vessel equipped with a stirrer, a thermometer and a reflux condenser was charged with 234 g of acetone as a reaction solvent. Under stirring, 40.00 g of 5-hydroxy-3,7-dithia-1,9-nonanediol as Compound A and 6.29 g of methyldiethanolamine as Compound C were added. After dissolution, the temperature was raised to 40 ° C., and 54.17 g of isophorone diisocyanate was added as Compound B. Thereafter, the temperature was raised to 50 ° C., and 0.1 g of dibutyltin laurate was added as a tin-based catalyst. The temperature was further raised to 55 ° C. and the reaction was carried out for 2 hours with stirring to obtain a polyaddition reaction product.

  After completion of the reaction, the reaction solution was cooled to room temperature, and 5.50 g of 35% by mass aqueous formic acid solution was added to cationize this polyaddition reaction product. Further, 410 g of water was added, and then the aqueous dispersion of the cationized polyaddition reaction product 7 having a solid concentration of 0.1% by mass was prepared in the same manner as in the method for producing the aqueous dispersion of the cationized polyaddition reaction product 1. Manufactured. The amount of compound C (methyldiethanolamine) used in the synthesis of the cationized polyaddition reaction product 7 is 11.1% in terms of molar ratio with respect to the total compound used to obtain the polyaddition reaction product. . As a result of measuring the average particle size of the aqueous dispersion of the obtained cationized polyaddition reaction product 7 using a laser particle size analyzer PARIII (trade name, manufactured by Otsuka Electronics Co., Ltd.), the aqueous dispersion 7 was 30 nm. It was.

<Example 1>
<Support>
A support was prepared under the following conditions. First, a paper stock having the following composition was prepared with water so that the solid content concentration was 3% by mass.

(Paper composition)
-Pulp 100 parts by mass (freezing degree 450 ml CSF (Canadian Standard Freeness), hardwood bleached kraft pulp (LBKP) (80 parts by mass),
And freezing kraft pulp (NBKP) (20 parts by mass)) having a freeness of 480 ml CSF.
-Cationized starch 0.60 mass part.
-Heavy calcium carbonate 10 mass parts.
-Light calcium carbonate 15 mass parts.
-Alkyl ketene dimer 0.10 mass part.
-Cationic polyacrylamide 0.030 mass part.

Next, this stock was made with a long paper machine, subjected to a three-stage wet press, and then dried with a multi-cylinder dryer. Thereafter, the starch starch aqueous solution was impregnated with a size press apparatus so that the coating amount was 1.0 g / m ² and dried. Thereafter, machine calendar finishing was performed to obtain a base paper having a basis weight of 170 g / m 2, a Steecht sizing degree of 100 seconds, an air permeability of 50 seconds, a Beck smoothness of 30 seconds, and a Gurley stiffness of 11.0 mN.

On the base paper, a resin composition composed of low density polyethylene (70 parts by mass), high density polyethylene (20 parts by mass), and titanium oxide (10 parts by mass) was applied at 25 g / m ² . Further, a resin-coated support is formed by applying 25 g / m ² of a resin composition comprising high-density polyethylene (50 parts by mass) and low-density polyethylene (50 parts by mass) to the back surface of the base paper. Obtained.

<Ink receiving layer>
On the support, an ink receiving layer coating solution having the following composition adjusted with water so that the solid content concentration was 20% by mass was applied with a slide die so that the dry coating amount was 35 g / m ² . Thereafter, the ink receiving layer was dried at 80 ° C. with a dryer to provide one ink receiving layer.
100 parts by mass of alumina hydrate (Dispersal. HP-14 (trade name) manufactured by SASOL, number-average secondary particle diameter: 160 nm).
1.5 parts by mass of methanesulfonic acid.
2.5 parts by mass of boric acid.
9.0 parts by mass of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., saponification degree 88 mol%, weight average polymerization degree 3500).

<Partial film>
A surfactant (trade name, TDX-50, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added to the aqueous dispersion of the cationized polyaddition reaction product 1 so that the dry solid content was 0.005% by mass. A coating liquid for coating was prepared. Subsequently, the ink reception by the Mayer bar so that the dry application amount (coating amount) of the cationized polyaddition reaction product 1 to the recording medium is 0.05 g / m ² with respect to the entire surface of the ink receiving layer. The coating solution was overcoated on the layer. Thereafter, the recording medium 1 was produced by drying at 60 ° C. for 20 minutes with a dryer, and the following evaluations 1 to 6 were performed. The results are shown in Table 1. Hereinafter, the dry coating amount may be referred to as a partial coating dry coating amount.

<Example 2>
A recording medium 2 was produced in the same manner as in Example 1 except that the dry coating amount of the partial coating was 0.02 g / m ² in Example 1, and the following evaluations 1 to 6 were performed. The results are shown in Table 1.

<Example 3>
A recording medium 3 was prepared in the same manner as in Example 1 except that the dry coating amount of the partial coating was 0.01 g / m ² in Example 1, and the following evaluations 1 to 6 were performed. The results are shown in Table 1.

<Example 4>
In Example 1, except that the dry coating amount of the partial coating was 0.1 g / m ² , the recording medium 4 was produced in the same manner as in Example 1, and the following evaluations 1 to 6 were performed. The results are shown in Table 1.

<Example 5>
A recording medium 5 was produced in the same manner as in Example 1 except that the dry coating amount of the partial coating was 0.008 g / m ² in Example 1, and the following evaluations 1 to 6 were performed. The results are shown in Table 1.

<Example 6>
A recording medium 6 was prepared in the same manner as in Example 1 except that the dry coating amount of the partial coating was 0.15 g / m ² in Example 1, and the following evaluations 1 to 6 were performed. The results are shown in Table 1.

<Example 7>
In Example 1, except that the aqueous dispersion of the cationized polyaddition reaction product 1 was replaced with the aqueous dispersion of the cationized polyaddition reaction product 2, and the dry coating amount of the partial coating was 0.008 g / m ^2. The recording medium 7 was produced in the same manner as in Example 1, and the following evaluations 1 to 6 were performed. The results are shown in Table 1.

<Example 8>
In Example 1, except that the aqueous dispersion of the cationized polyaddition reaction product 1 was replaced with the aqueous dispersion of the cationized polyaddition reaction product 3, and the dry coating amount of the partial coating was 0.1 g / m ^2. The recording medium 8 was produced in the same manner as in Example 1, and the following evaluations 1 to 6 were performed. The results are shown in Table 1.

<Example 9>
A recording medium 9 was produced in the same manner as in Example 1 except that the aqueous dispersion of the cationized polyaddition reaction product 1 was replaced with the aqueous dispersion of the cationized polyaddition reaction product 4 in Example 1. The following evaluations 1 to 6 were performed. The results are shown in Table 1.

<Example 10>
A recording medium 10 was prepared in the same manner as in Example 1 except that the aqueous dispersion of the cationized polyaddition reaction product 1 was replaced with the aqueous dispersion of the cationized polyaddition reaction product 5 in Example 1. The following evaluations 1 to 6 were performed. The results are shown in Table 1.
<Example 11>
A recording medium 11 was prepared in the same manner as in Example 1 except that the aqueous dispersion of the cationized polyaddition reaction product 1 was replaced with the aqueous dispersion of the cationized polyaddition reaction product 6 in Example 1. The following evaluations 1 to 6 were performed. The results are shown in Table 1.
<Example 12>
A recording medium 12 was prepared in the same manner as in Example 1 except that the aqueous dispersion of the cationized polyaddition reaction product 1 was replaced with the aqueous dispersion of the cationized polyaddition reaction product 7 in Example 1. The following evaluations 1 to 6 were performed. The results are shown in Table 1.

<Comparative Example 1>
In Example 1, a recording medium 13 was prepared in the same manner as in Example 1 except that the partial coating using the aqueous dispersion of the cationized polyaddition reaction product 1 was not provided, and the following evaluations 1 to 6 were performed. . The results are shown in Table 1.

<Comparative example 2>
In Example 1, a recording medium 14 was produced in the same manner as in Example 1 except that the dry coating amount of the partial coating was 0.3 g / m ^2, and the following evaluations 1 to 6 were performed. The results are shown in Table 1. The outermost film of the recording medium 14 is a complete film as judged by the following criteria, and does not fall under the present invention.

<Comparative Example 3>
In Example 1, instead of the aqueous dispersion of the cationized polyaddition reaction product 1, a 0.1 mass% aqueous dispersion of 2,6-dithia-1,8-octanediol was dried in an amount of 0.05 g. / M ² was overcoated on the ink receiving layer. Otherwise, the recording medium 15 was produced in the same manner as in Example 1, and the following evaluations 1 to 6 were performed. The results are shown in Table 1.

<Comparative example 4>
In Example 1, instead of the aqueous dispersion of the cationized polyaddition reaction product 1, a polyurethane emulsion “Superflex 620” (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., 25 mass% aqueous solution) was added in an amount of 0.1. What was adjusted to the mass% aqueous solution was used. Further, the ink receiving layer was overcoated so that the dry coating amount was 0.05 g / m ² . Other than that, the recording medium 16 was produced like Example 1, and the following evaluations 1-6 were performed. The results are shown in Table 1.

<Comparative Example 5>
In Example 1, instead of the aqueous dispersion of the cationized polyaddition reaction product 1, 70 parts by mass of “Superflex 620” (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 2,6-dithia 1, An aqueous dispersion (solid content concentration: 0.1% by mass) containing 30 parts by mass of 8-octanediol was applied so that the dry coating amount was 0.05 g / m ² . Other than that, the recording medium 17 was produced like Example 1, and the following evaluations 1-6 were performed. The results are shown in Table 1.

<Comparative Example 6>
In Example 1, instead of overcoating the aqueous dispersion of the cationized polyaddition reaction product 1 on the ink receiving layer, the ink receiving layer coating liquid used in Example 1 had a solid concentration of 20% by mass. It changed to the coating liquid for ink receptive layers of the following composition adjusted with water so that it might become. Moreover, the partial membrane | film | coat was not provided. Otherwise, the recording medium 18 was produced in the same manner as in Example 1, and the following evaluations 1 to 6 were performed. The results are shown in Table 1.
Alumina hydrate 100 parts by mass (Dispersal. HP-14 (trade name) manufactured by SASOL, number average secondary particle size 160 nm).
-Methanesulfonic acid 1.5 mass part.
-2.5 parts by mass of boric acid.
-9.0 mass parts of polyvinyl alcohol (the Kuraray Co., Ltd. make, saponification degree 88 mol%, weight average polymerization degree 3500).
-Cationized polyaddition reaction product 1 0.2 parts by weight.

<Comparative Example 7>
In Example 1, instead of overcoating the aqueous dispersion of the cationized polyaddition reaction product 1 on the ink receiving layer, the ink receiving layer coating liquid used in Example 1 was changed to the following composition, No film was provided. Otherwise, the recording medium 19 was produced in the same manner as in Example 1, and the following evaluations 1 to 6 were performed. The results are shown in Table 1.
Alumina hydrate 100 parts by mass (Dispersal. HP-14 (trade name) manufactured by SASOL, number average secondary particle size 160 nm).
-Methanesulfonic acid 1.5 mass part.
-2.5 parts by mass of boric acid.
-9.0 mass parts of polyvinyl alcohol (the Kuraray Co., Ltd. make, saponification degree 88 mol%, weight average polymerization degree 3500).
-Cationized polyaddition reaction product 1 10 mass parts.

[Evaluation]
<Evaluation 1: Coating rate of partial coating>
It was first determined whether the cationized polyaddition reaction product was partially coated or completely coated on the recording surface (surface having the ink receiving layer (and partial coating)) of each recording medium obtained. First, the entire surface was observed with an electron microscope (SEM Hitachi S-4300 (trade name)) at a magnification of 30,000 times, and the pores of the ink receiving layer were blocked. Yes, when a part of the pores of the ink receiving layer was observed, it was judged as a partial film.
When it was determined that the film was a partial film, any 10 or more locations on the recording surface were observed at a magnification of 30,000 times. The obtained images were read with Adobe Photoshop (trade name), respectively, and the pores of the ink receiving layer, the alumina hydrate, and the cationized polyaddition reaction product partially coated on the surface were adjusted to give contrast. Then, the ratio which occupied the brightness | luminance of the cationization polyaddition reaction product partially coat | covered on the surface was calculated | required with the brightness | luminance histogram, and the average value of ten or more images was calculated | required as the film ratio of each recording medium.

<Evaluation 2: Film size of partial film>
The recording surface (surface having the ink receiving layer (and partial coating)) of each recording medium obtained was subjected to an electron microscope (SEM Hitachi S-4300 (trade name)) at any 100 locations on the recording surface. Was observed at a magnification of 30,000 times. For each partial film of each recording medium, the average value of the film portions taken so that the length from end to end of the film portion was the longest was obtained as the film size.

<Evaluation 3: Surface gloss>
About the recording surface (surface which has an ink receiving layer (and partial film | membrane)) of each obtained recording medium, it uses a gloss meter (brand name: VG-2000, Nippon Denshoku Industries Co., Ltd. product), and 75 degrees. The gloss was measured and evaluated based on the following evaluation criteria.

・ Evaluation criteria 5: 80 or more,
4: 70 to less than 80,
3: 60 to less than 70,
2: 50 or more and less than 60,
1: Less than 50.

<Evaluation 4: Print density (color development)>
A black (Bk) ink was solid-printed with an ink amount of 100% on each of the produced recording media using an inkjet recording apparatus (trade name: BJ F870, manufactured by Canon Inc.), and the optical density was measured with an optical reflection densitometer (Greta Macbeth). The product name was measured using a product name: RD-918). Each recording medium was evaluated based on the following evaluation criteria.

-Evaluation criteria 5: 2.20 or more,
4: 2.10 or more and less than 2.20,
3: 2.00 or more and less than 2.10,
2: 1.90 or more and less than 2.00,
1: Less than 1.90.

<Evaluation 5: Ink absorbability>
An ink jet recording apparatus (trade name: BJ F870, manufactured by Canon Inc.) was used for each recording medium, and the ink was applied in an amount of 90% to 270% and green (mixed of cyan ink / photocyan ink / yellow ink). Solid printing with a ratio of 85/90/100) was performed. The maximum amount of beading that did not cause beading was determined, and ink absorbency was evaluated based on the following evaluation criteria.

・ Evaluation criteria ○: ink ejection amount of 200% or more,
(Triangle | delta): The amount of ink placement is 170% or more and less than 200%,
X: The amount of ink applied is less than 170%.

<Evaluation 6: Ozone resistance>
Solid recording was performed on each of the recording media using a black (Bk) ink and an ink amount of 100% using an inkjet recording apparatus (trade name: BJ F870, manufactured by Canon Inc.). Next, each printed recording medium is put in an ozone exposure tester (made by Suga Test Instruments Co., Ltd., special order) and exposed to ozone at a concentration of 1 volume ppm for 4 hours under the conditions of 40 ° C and 55% RH (relative humidity). did. Then, Bk optical density (OD) was measured using an optical reflection densitometer (manufactured by Greta Macbeth Co., Ltd., trade name: RD-918), and the residual OD rate was calculated from the following formula to determine the fading / discoloration due to ozone exposure. Evaluation was performed based on the evaluation criteria.

Residual OD rate = (OD after test / OD before test) × 100%
-Evaluation criteria 6: 90% or more,
5: 80% or more and less than 90%,
4: 70% or more and less than 80%,
3: 60% or more and less than 70%,
2: 50% or more and less than 60%,
1: Less than 50%.

From the above results, in the recording media of Examples 1 to 12, the partial film containing the cationized polyaddition reaction product was provided on the ink receiving layer by providing the partial film containing the cationized polyaddition reaction product. Compared with Comparative Example 1 that does not, glossiness and ozone resistance were clearly improved. In addition, in Examples 1 to 12, glossiness and color development were clearly improved as compared with Comparative Example 3 in which a diol having a sulfide group of 3,6-dithia-1,8-octanediol was overcoated. It was. In Comparative Example 3, 3,6-dithia-1,8-octanediol permeated into the ink receiving layer, so that excellent ozone resistance could not be obtained. Further, when one week has passed in a low temperature environment, the thioether compound may be deposited on the surface of the recording medium, and the appearance may be deteriorated.
Moreover, although the comparative example 4 which produced the partial membrane | film | coat used for this invention using the polyurethane which has no reducibility with respect to ozone gas had the glossiness improvement effect, the effect was not acquired regarding ozone resistance. In Comparative Example 5, the thioether-based compound was deposited on the surface of the recording medium after 1 week in a low temperature environment, and the appearance sometimes deteriorated. By simultaneously overcoating Superflex 620, the ozone resistance was improved as compared with Comparative Example 3, but the glossiness was insufficient.
Further, in Comparative Examples 6 and 7 in which the cationized polyaddition reaction product used in the present invention was contained in the ink receiving layer, no gloss improvement effect was obtained, and it was difficult to achieve both color developability and ozone resistance. In Comparative Example 2 in which the partial film containing the cationized polyaddition reaction product used in the present invention was used as a complete film on the ink receiving layer, although excellent gloss was obtained, the ink absorbability was remarkably lowered.
That is, all items of glossiness, color development, ink absorption and ozone resistance are provided by providing a partial film containing the cationized polyaddition reaction product used in the present invention on the outermost surface, which is the configuration of the present invention. We were able to achieve a satisfactory level.

Claims (4)

A recording medium having at least one ink receiving layer on a support,
The outermost surface has a partial film containing a cationized polyaddition reaction product, and the cationized polyaddition reaction product contains a sulfur-containing organic compound (A) having two or more active hydroxyl groups, 2 isocyanate groups. A compound obtained by cationizing at least part of the amino group of the polyaddition reaction product of at least one of the polyisocyanate compound (B) having two or more and the amine compound (C) having two or more active hydroxyl groups. A recording medium characterized by being.   The recording medium according to claim 1, wherein the coating rate of the partial coating is 10% or more and less than 70%, and the size of the partial coating is 0.03 μm or more and less than 1 μm. The coating amount of the cationized polyaddition reaction product is 0.01 g / m ² or more and 0.1 g / m ² or less with respect to the entire surface of the ink receiving layer. Recording media.   The amount of the amine compound (C) used for obtaining the polyaddition reaction product is 5.5% or more and 18.5 in a molar ratio with respect to the total compound used for obtaining the polyaddition reaction product. The recording medium according to claim 1, wherein the recording medium is not more than%.