KR20120129818A - Inkjet recording medium - Google Patents

Abstract

PURPOSE: An inkjet recording medium is provided to improve the color fixation characteristic and the ink absorption characteristic of the inkjet recording media by including an ink receiving layer. CONSTITUTION: An inkjet recording medium includes a support and an ink receiving layer. The ink receiving layer is installed on the support and includes an alumina pigment, C1-4 alkyl sulfonic acid, a polymeric compound, a water soluble zirconium compound, and boric acid or borate. The polymeric compound is obtained by cationizing a sulfur containing organic compound, polyisocyanate, and the resultant product of at least three of amine compounds containing two or more active hydrogen atoms. The polymeric compound is represented by one of chemical formulas including chemical formula 1. The sulfur containing organic compound contains two or more active hydrogen atoms. The polyisocyanate compound contains two or more isocyanate groups.

Description

Inkjet recording medium {INKJET RECORDING MEDIUM}

The present invention relates to an inkjet recording medium.

An ink jet recording medium used in the ink jet recording method usually includes an ink receiving layer containing a binder such as polyvinyl alcohol and inorganic pigments such as silica and alumina hydrate held in the binder. Inkjet recording media are required to have color development, moisture resistance and ink absorption. In addition, the ink receiving layer is required to be resistant to cracks and scratches when the inkjet recording medium is conveyed from the printer.

Japanese Patent Laid-Open No. 2006-15655 (hereinafter referred to as Patent Document 1) discloses an inkjet recording medium comprising a support and an ink receiving layer provided thereon. This ink receiving layer is formed using a coating liquid containing an aqueous dispersion of at least one water-soluble polyvalent metal salt and a cationized modified self-emulsifying polymer. The average particle size of the aqueous dispersion is 0.05 μm or less. Self-emulsifying polymers are cationic urethane polymers.

Japanese Laid-Open Patent Publication No. 2005-336480 (hereinafter referred to as Patent Document 2) includes an ink receiving layer containing an alumina hydrate and a cationic urethane compound, and an inkjet recording medium having excellent moisture resistance, gas resistance and light resistance is Is disclosed.

According to the examination of the present inventors, it was shown that the inkjet recording medium containing the ink receiving layer containing the cationic urethane polymer disclosed in Patent Literature 1 has room for improvement in ink absorption at high speed printing. In addition, according to the above examination, the inkjet recording medium disclosed in Patent Literature 2 has room for improvement in ink absorbency at the time of high speed printing, and there is room for improvement in scratch resistance of the ink receiving layer during conveyance in a printer.

The present invention provides an inkjet recording medium comprising an ink receiving layer. This inkjet recording medium has high color development, moisture resistance and ink absorption at high speed. This inkjet recording medium ensures crack resistance and scratch resistance of the ink receptive layer when conveyed by a printer.

One embodiment of the present invention, the support and

An inkjet recording medium provided on the support and comprising an ink receiving layer containing an alumina pigment, an alkyl sulfonic acid having 1 to 4 carbon atoms, a polymer compound, a water-soluble zirconium compound, and boric acid or a borate salt. The ink receiving layer is 0.5 parts by mass to 8 parts by mass of the polymer compound, 0.15 parts by mass to 3 parts by mass of the water-soluble zirconium compound, and 0.8 parts by mass to 3 parts by mass of the boric acid or borate, per 100 parts by mass of the alumina pigment. Contains; The polymer compound includes (i) a sulfur-containing organic compound containing two or more active hydrogen atoms, (ii) a polyisocyanate compound containing two or more isocyanate groups, and (iii) an amine containing two or more active hydrogen atoms. At least one amino group of the product obtained by the reaction of at least three compounds of the compound is obtained by cationating with an acid; When the mass part of the said polymer compound is represented by A per 100 mass parts of alumina pigments, and the mass part of the said water-soluble zirconium compound is represented by B per 100 mass parts of alumina pigments, ratio B / A is 0.02 or more and 6 or less.

An inkjet recording medium including an ink receiving layer can be provided. This inkjet recording medium has high color development, moisture resistance, and ink absorption at high speed. This inkjet recording medium ensures crack resistance and scratch resistance of the ink receptive layer when conveyed by a printer.

Further features of the present invention will become apparent from the description of the following exemplary embodiments.

EMBODIMENT OF THE INVENTION Hereinafter, the inkjet recording medium which concerns on preferable embodiment of this invention is demonstrated in detail. The inkjet recording medium includes a support and an ink receiving layer provided on at least one surface of the support.

<Support>

The support is preferably made of paper such as cast coated paper, baritage or polymer coated paper (paper coated with a polymer such as polyolefin) or made of a film. In particular, the support is preferably made of a polymer coated paper in view of the glossiness of the ink receptive layer. The film is preferably a transparent thermoplastic polymer film made of polyethylene, polypropylene, polyester, polylactic acid, polystyrene, polyacetate, polyvinyl chloride, cellulose acetate, polyethylene terephthalate, polymethyl methacrylate or polycarbonate.

In addition, the following materials can be used to form the support: an absorbent paper that is a suitably sized paper; Coated paper; Or sheet-like materials such as synthetic paper made of an opaque film containing inorganic matter or fine bubbles. Alternatively, sheets of glass or metal may be used to form the support. In order to improve the adhesive strength between the support and the ink receiving layer, the support may be surface treated with corona discharge, undercoat, or the like.

<Ink receiving layer>

(Alumina pigment)

The ink receiving layer contains an alumina pigment. It is preferable that an alumina pigment contains an alumina hydrate. It is preferable that alumina hydrate has the following general formula (X).

<Formula X>

Wherein n is 0, 1, 2 or 3, and m is preferably 0 to 10, more preferably 0 to 5, provided that m and n are not zero at the same time. In Formula X, mH ₂ O does not participate in the formation of the crystal lattice and represents a detachable aqueous phase, so m may be an integer or not an integer. By heating m can be zero.

The alumina hydrate is present in amorphous form or in the form of gibbsite or boehmite, depending on the heat treatment temperature, and may have any crystal structure. It is particularly preferable that the alumina hydrate is in the form of boehmite or amorphous in characterization by X-ray diffraction. In particular, the alumina hydrate may be any of those disclosed in Japanese Patent Laid-Open Nos. 7-232473, 8-132731, 9-66664 and 9-76628. The alumina hydrate is preferably selected so that the average pore radius of the ink receiving layer at the time of forming the ink receiving layer is 7.0 nm or more and 10 nm or less. As for the average void radius of an ink receiving layer, it is more preferable that it is 8.0 nm or more. When the average void radius of the ink receiving layer is within the above range, the ink receiving layer can exhibit excellent ink absorbency and color development. If the average void radius of the ink receiving layer is smaller than the above range, the ink absorbency is insufficient, and therefore, even if the amount of the binder to the alumina hydrate is adjusted, sufficient ink absorbency may not be achieved. If the average void radius of the ink receiving layer is larger than the above range, the haze of the ink receiving layer becomes large, and therefore, sufficient color development may not be achieved. It is preferable that no space | gap of 25 nm or more exists in an ink receiving layer. When the space | gap of 25 nm or more exists, the haze of an ink accommodating layer becomes large and therefore sufficient color development may not be exhibited.

The total void volume of the ink receiving layer is preferably 0.50 ml / g or more. If the total pore volume is less than 0.50 ml / g, the ink absorbency of the ink receiving layer is insufficient, and therefore, even if the amount of the binder to the alumina hydrate is adjusted, sufficient ink absorption may not be achieved.

The average pore radius and total pore volume are values measured by the Barrett-Joyner-Halenda (BJH) method from the nitrogen adsorption desorption isotherm obtained by measuring the recording medium by the nitrogen adsorption desorption method. In particular, the mean pore radius is a value calculated from the total pore volume and specific surface area measured by nitrogen desorption.

When the inkjet recording medium is measured by nitrogen adsorption desorption, portions other than the ink receiving layer are also measured. However, components other than the ink receiving layer (for example, the support, the polymer coating, etc.) do not have pores of 1 to 100 nm which can be generally measured by nitrogen adsorption desorption. Therefore, when the whole inkjet recording medium is measured by nitrogen adsorption desorption method, it is estimated that it is the same as measuring the average void radius of an ink receiving layer. This is inferred from the fact that the polymer coated paper does not have pores of 1 to 100 nm when the pore distribution is measured by nitrogen adsorption desorption.

To the ink receiving layer so as to have the mean pore radius, is the BET specific surface area of the alumina hydrate is more preferably 100m ² / g more than 200m ² / g and preferably, 125m ² / g or less than 175m ² / g or less. The BET method is one of methods for measuring the surface area of particles by vapor phase adsorption, and is a technique for measuring the surface area of a sample of 1 g, that is, its specific surface area, from an adsorption isotherm. In the BET method, nitrogen gas is usually used as the adsorption gas, and the method of measuring the adsorption amount from the change in pressure or volume of the adsorption gas is most widely used. The Brunauer-Emmett-Teller equation is one of the most popular equations for expressing multimolecular adsorption isotherms, called the BET equation, and is widely used to find specific surface areas. In the BET method, the adsorption amount is determined by the BET formula, and the specific surface area is obtained by multiplying the adsorption amount by the area occupied by one adsorbed molecule. In the BET method, the amount of adsorption at the relative pressure by the nitrogen adsorption desorption method is measured several times, the slope and y-intercept of the relationship between them are obtained, and the specific surface area is derived from the slope and the y-intercept. Therefore, in order to raise the precision of a measurement, it is preferable to measure the relationship of adsorption amount and relative pressure at least 5 times, and it is more preferable to measure 10 times or more.

It is preferable that the particle | grains of an alumina hydrate are flat form, the average aspect ratio is 3.0 or more and 10 or less, and the vertical horizontal ratio of a flat surface is 0.60 or more and 1.0 or less. Aspect ratio can be calculated | required by the method disclosed by Unexamined-Japanese-Patent No. 5-16015. The aspect ratio is expressed here as the ratio of the diameter to the thickness of the particles. As used herein, the term "diameter" refers to the diameter of a circle (circle equivalent diameter) having an area equal to the projected area of the particles of alumina hydrate observed under a microscope or electron microscope. The vertical horizontal ratio of the flat surface is defined as the ratio of the longitudinal size to the transverse size of the flat surface observed under the microscope, similarly to the aspect ratio. If the aspect ratio of the alumina hydrate is out of the above range, the pore distribution of the ink receiving layer may be narrowed. Therefore, it is difficult to synthesize alumina hydrate so that the alumina hydrate has a uniform particle size. Similarly, when the vertical horizontal ratio is outside the above range, the pore distribution of the ink receiving layer is narrowed.

Ciliated alumina hydrates and non-ciliform aluminum hydrates are well known. According to the findings of the present inventors, the flat alumina hydrate has better dispersibility than the ciliated alumina hydrate. The ciliated alumina hydrate is oriented parallel to the surface of the support at the time of coating, and the voids formed are small, thus the ink absorption of the ink receiving layer is low. In contrast, flat alumina hydrates tend to be less oriented in coating and less likely to adversely affect the size of the voids formed in the ink receiving layer and the ink absorbency of the ink receiving layer. Therefore, it is preferable to use flat alumina hydrate.

A preferred example of alumina hydrate is DISPERAL HP14 available from Sasol.

(Other alumina pigments)

In addition to the alumina hydrate, the ink receiving layer may further contain other alumina pigments such as γ-alumina, α-alumina, δ-alumina, θ-alumina or χ-alumina. In particular, γ-alumina (hereinafter referred to as “weather alumina”) synthesized by the vapor phase method is preferable from the viewpoint of ink absorption and scratch resistance at the time of conveyance. (gamma) -alumina is obtained by heating the alumina hydrate manufactured by a well-known method at the temperature of 400 degreeC or more and 900 degrees C or less, and then baking.

From the viewpoint of ink absorbency and scratch resistance at the time of conveyance, the vapor phase alumina is preferably one having a BET specific surface area smaller than that of the alumina hydrate, that is, having a large primary particle size. The mechanism by which the scratch resistance is improved is not clear, but is estimated as follows. When the flat particles of the alumina hydrate are present on the surface of the recording medium (the surface of the first ink receiving layer), upon pressurization by the conveying roller, the recording medium is deformed and the direction of the flat particles present therein changes, thus The glossiness of the recording medium changes slightly. By the change of the glossiness, the scratch which arises at the time of conveyance becomes conspicuous. On the other hand, the particles of the vapor phase alumina are relatively close in spherical shape and are isotropic in shape, and therefore, even if the direction of the particles changes, the change in glossiness thereof is relatively small. For this reason, it is estimated that the abrasion which arises at the time of conveyance becomes difficult to stand out.

It is preferable that it is 50 g / m <^2> or more, and, as for the BET specific surface area of vapor phase alumina, it is more preferable that it is 80 g / m <^2> or more. It is preferable that it is 150 g / m <^2> or less, and, as for the BET specific surface area of vapor phase alumina, it is more preferable that it is 120 g / m <^2> or less. It is preferable that it is 5 nm or more, and, as for the primary particle size of vapor phase alumina, it is more preferable that it is 11 nm or more. It is preferable that it is 30 nm or less, and, as for the primary particle size of vapor phase alumina, it is more preferable that it is 15 nm or less.

Meteorological alumina may be commercially available. Examples of commercially available products include AEROXIDE AluC (primary particle size 13 nm, BET specific surface area of 100 g / m ² , commercially available from EVONIC); Aeroxide Alu130 (primary particle size 10 nm, BET specific surface area 130 g / m ² , available from Evonik); And aeroxide Alu65 (primary particle size 20 nm, BET specific surface area 65 g / m ² , sold by Evonik).

Use of Aeroxide AluC and Aeroxide Alu65 is preferable because ink absorption is improved and scratch resistance at the time of conveyance is improved. It is especially preferable to use aeroxide AluC because it suppresses the deterioration of color development. The mass ratio of alumina hydrate to vapor phase alumina is preferably 100: 0 to 70:30, more preferably 60:40 to 95: 5, and even more preferably 70:30 to 90:10.

(bookbinder)

It is preferable that an ink receiving layer contains a binder. The binder is a material capable of binding alumina hydrate and forming a coating. The binder is not particularly limited unless it reduces the advantages of the present invention. Examples of the binder include starch derivatives such as oxidized starch, etherified starch, and starch esterified with phosphoric acid; Cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose; Casein; Casein derivatives; Gelatin derivatives; Soy protein; Soy protein derivatives; Polyvinyl alcohol; Polyvinyl alcohol derivatives; Conjugated polymer latexes such as polyvinylpyrrolidone, maleic anhydride polymer, styrene-butadiene copolymer and methyl methacrylate-butadiene copolymer; Acrylic polymer latexes such as acrylic acid ester polymers and methacrylic acid ester polymers; Vinyl polymer latexes such as ethylene-vinyl acetate copolymers; Functional group-modified polymer latex produced from monomers containing functional groups such as carboxyl groups of the polymer; Prepared by cationizing the polymer with a cationic agent; Prepared by surface cationization of the polymer with a cationic surfactant; Prepared by polymerizing the polymer in the presence of cationic polyvinyl alcohol such that polyvinyl alcohol is distributed in the polymer; Prepared by polymerizing the polymer in a suspension or dispersion of cationic colloidal particles such that the cationic colloidal particles are distributed in the polymer; Aqueous binders derived from thermosetting polymers such as melamine polymers and urea polymers; Polymers or copolymers such as polymethyl methacrylate prepared from acrylic acid esters or methacrylic acid esters; And synthetic polymer binders such as polyurethane polymers, unsaturated polyester polymers, polyvinylchloride-vinyl alcohol copolymers, polyvinyl butyral and alkyd polymers.

These materials may be used alone or in combination. In particular, polyvinyl alcohol is most preferred. Polyvinyl alcohol can usually be obtained by hydrolyzing polyvinyl acetate. It is preferable that it is 1,500 or more, and, as for the average polymerization degree of polyvinyl alcohol, it is more preferable that it is 2,000 or more and 5,000 or less. It is preferable that it is 80 or more and 100 or less, and, as for the saponification degree of polyvinyl alcohol, it is more preferable that it is 85 or more and 100 or less.

It is preferable that they are 7.0 mass% or more and 12.0 mass% or less of an alumina hydrate, and, as for content of the polyvinyl alcohol in an ink receiving layer, it is more preferable that they are 8.0 mass% or more and 9.0 mass% or less. If content is less than 7.0 mass%, a high strength coating is hard to be formed. When content exceeds 12.0 mass%, gelatinization is accelerated | stimulated and coating property may fall.

(Discourse)

The ink receiving layer contains a peptizing agent such as alkylsulfonic acid having 1 to 4 carbon atoms in order to stably disperse the alumina hydrate. When a sulfonic acid containing 5 or more carbon atoms or a sulfonic acid containing a benzene ring is used as a peptizing agent, the color stability and the image density fall easily. The reason for this is that the peptizing agent becomes more hydrophobic due to the increase in the number of carbon atoms, and therefore the surface of the alumina becomes more hydrophobic. When alumina hydrates are peptized with an alkylsulfonic acid containing 5 or more carbon atoms or a sulfonic acid containing a benzene ring, it is difficult to achieve sufficient dispersion stability, the thickening easily occurs, the productivity decreases, and the alumina hydrate aggregates. A decrease in image density occurs.

The alkyl sulfonic acid having 1 to 4 carbon atoms is preferably a monobasic acid containing only a sulfo group as the solubilizing group. It is preferable from a viewpoint of moisture resistance that C1-C4 alkyl sulfonic acid contains the alkyl group which does not have solubilizing groups, such as a hydroxyl group or a carboxyl group. The alkyl group is preferably unsubstituted. Alkyl groups may be straight or branched. Preferred examples of the alkyl sulfonic acid include methanesulfonic acid, ethanesulfonic acid, isopropanesulfonic acid, n-propanesulfonic acid, n-butanesulfonic acid, isobutanesulfonic acid and t-butanesulfonic acid. In particular, methanesulfonic acid, ethanesulfonic acid, isopropanesulfonic acid and n-propanesulfonic acid having 1 to 3 carbon atoms are preferable. Methanesulfonic acid is particularly preferred.

It is preferable that content of C1-C4 alkylsulfonic acid in an ink receiving layer is 1.0 mass part or more and 2.0 mass parts or less per 100 mass parts of alumina pigments. When content is less than 1.0 mass part, the ozone resistance of an ink receiving layer may fall. When content exceeds 2.0 mass parts, the ink absorption of an ink receiving layer may not be favorable. As for content, it is more preferable that it is 1.3 mass parts or more and 1.6 mass parts or less.

(Water soluble zirconium compound)

The ink receptive layer contains a water-soluble zirconium compound for the purpose of achieving improvement in scratch resistance and ink absorption. Examples of the water-soluble zirconium compound include zirconium acetate, zirconium nitrate, zirconium sulfate, zirconium carbonate ammonium, potassium zirconium carbonate and zirconium chloride. In particular, zirconium acetate is preferable because the alumina coating liquid can be added most easily without impairing the dispersibility of the alumina coating liquid. The addition amount of a water-soluble zirconium compound is 0.15 mass part or more and 3 mass parts or less per 100 mass parts of alumina pigments. If the amount is less than 0.15 parts by mass, the effect of scratch resistance is low. When the addition amount exceeds 3 parts by mass, there is a possibility that the ink receiving layer is cracked (cracking at the time of bending) when the inkjet recording medium is substantially filled at the time of transport. It is preferable that addition amount is 0.3 mass part or more and 1 mass part or less.

(Borate or borate)

The ink receiving layer contains boric acid or borate, which is a component for crosslinking of the binder, in addition to the water-soluble zirconium compound, for the purpose of achieving improvement of scratch resistance and ink absorption. Content of boric acid or a borate in an ink receiving layer is 0.8 mass part or more and 3 mass parts or less per 100 mass parts of alumina pigments. If the content is less than 0.8 parts by mass, the ink absorption and scratch resistance of the ink receiving layer are insufficient. When the content exceeds 3 parts by mass, there is a possibility that the ink receiving layer is cracked (cracking at the time of bending) when the inkjet recording medium is considerably filled during transportation. It is preferable that content is 1 mass part or more and 3 mass parts or less, and it is more preferable that they are 1 mass part or more and 2 mass parts or less. One example of a borate salt is sodium borate.

(Polymer compound)

The ink receptive layer contains a polymer compound. The polymeric compound is at least three compounds, i.e. sulfur containing organic compounds containing two or more active hydrogen atoms (hereinafter referred to as compound (i)), polyisocyanate compounds containing two or more isocyanate groups (hereafter compound (ii ), And at least one amino group of the product obtained by the reaction of an amine compound containing two or more active hydrogen atoms (hereinafter referred to as compound (iii)) with an acid. The weight average molecular weight of the polymer compound is 2,000 to 150,000. The polymer compound may be at least one selected from the group consisting of compounds represented by the following formulas.

In the formula, n represents 1 or 2, R ₁ represents a methylene group, an ethylene group or a propylene group, R ₉ represents an alkylene group or an aliphatic hydrocarbon group containing at least one polyalicyclic group (alicyclic structure), R ₁₀ represents an alkyl group having 1 to 4 carbon atoms, R ₁₁ and R ₁₂ independently represent a hydrogen atom or a methyl group, and X ⁻ represents an acid anion.

Wherein n represents 1 or 2, R ₂ and R ₃ independently represent a hydrogen atom, a hydroxyl group or an alkyl group, may be the same or different from each other, and R ₉ is an alkylene group or one or more polyalicyclic rings An aliphatic hydrocarbon group containing a group group (alicyclic structure) is represented, R ₁₀ represents an alkyl group having 1 to 4 carbon atoms, R ₁₁ and R ₁₂ independently represent a hydrogen atom or a methyl group, and X ⁻ represents an acid anion.

In the formula, n represents 0 or 1, R ₉ represents an alkylene group or an aliphatic hydrocarbon group containing at least one polyalicyclic group (alicyclic structure), R ₁₀ represents an alkyl group having 1 to 4 carbon atoms, R ₁₁ and R ₁₂ independently represent a hydrogen atom or a methyl group, and X ⁻ represents an acid anion.

In the formula, n represents 1 or 2, R ₄ represents a sulfur atom or an oxygen atom, R ₅ represents a sulfur atom or a sulfonyl group, R ₄ and R ₅ are different from each other, R ₉ is an alkylene group, or An aliphatic hydrocarbon group containing at least one polyalicyclic group (alicyclic structure), R ₁₀ represents an alkyl group having 1 to 4 carbon atoms, R ₁₁ and R ₁₂ independently represent a hydrogen atom or a methyl group, and X ⁻ represents Acid anion.

Wherein R ₆ and R ₇ independently represent a hydrogen atom or a methyl group, may be the same or different from each other, and R ₉ represents an alkylene group or an aliphatic hydrocarbon group containing one or more polyalicyclic groups (alicyclic structures). R ₁₀ represents an alkyl group having 1 to 4 carbon atoms, R ₁₁ and R ₁₂ independently represent a hydrogen atom or a methyl group, and X ⁻ represents an acid anion.

In formula, R <_8> represents a hydroxyl group or an alkyl group, R <_9> represents an alkylene group or the aliphatic hydrocarbon group containing 1 or more polyalicyclic group (alicyclic structure), R <_10> is C1-C4 alkyl group Represents R ₁₁ and R ₁₂ independently represent a hydrogen atom or a methyl group, and X ⁻ represents an acid anion. In Formulas 1 to 6, m is determined such that the weight average molecular weight of the polymer compound is within the above range.

The compound (i) used for the synthesis of the polymer compound is not particularly limited, and preferably contains at least one sulfide group. In particular, the compound (i) may be at least one selected from the group consisting of compounds represented by the following formulas.

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

In formula, n represents 1 or 2, R <_2> and R <_3> represents a hydrogen atom, a hydroxyl group, or an alkyl group independently, and may be same or different from each other.

In formula, n represents 0 or 1.

In the formula, n represents 1 or 2, R ₄ represents a sulfur atom or an oxygen atom, R ₅ represents a sulfur atom or a sulfonyl group, and R ₄ and R ₅ are different from each other.

In the formula, R ₆ and R ₇ independently represent a hydrogen atom or an alkyl group, and may be the same or different from each other.

In the formula, R ₈ represents a hydroxyl group or an alkyl group. In particular, the compound represented by the formula (8) or (12) is preferable because it is very effective in suppressing image discoloration due to light or acidic gas in the atmosphere. These compounds may be used alone or in combination to synthesize polymer compounds.

Examples of compound (ii) used for the synthesis of the polymer compound 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-hexamethylene diisocyanate, dodeca Methylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xyl There can be a diisocyanate, lysine diisocyanate, isophorone diisocyanate and 4,4'-dicyclohexylmethane diisocyanate, and the like. These compounds may be used alone or in combination to synthesize polymer compounds.

The compound (iii) used for the synthesis of the polymer compound is preferably, for example, a tertiary amine represented by the following formula.

Wherein one of R ₁ , R ₂ and R ₃ represents an alkyl group, an alkanol group or an aminoalkyl group containing 1 to 6 carbon atoms, the others may be the same or different from one another and are alkanol groups, aminoalkyl groups or alkanes A thiol group is shown.

Examples of compound (iii) include N-methyl-N, N-diethanolamine, N-ethyl-N, N-diethanolamine, N-isobutyl-N, N-diethanolamine, Nt-butyl-N Diol compounds such as, N-diethanolamine and Nt-butyl-N, N-diisopropanolamine; Triol compounds such as triethanolamine; Diamine compounds such as methyliminobispropylamine and butyliminobispropylamine; And triamine compounds such as tri (2-aminoethyl) amine. These compounds may be used alone or in combination to synthesize polymer compounds.

The polymer compound is prepared by reaction of compound (i), compound (ii) and compound (iii) with a compound (i) unit, a compound (ii) unit and a compound (iii) unit (wherein the unit is a cationized tertiary amine). In the form of a polymer). It is preferable that content of the compound (iii) in a polymer compound is 5.5% or more and 18.5% or less by molar ratio. If the content of the compound (iii) is less than 5.5% in molar ratio, the content of the hydrophilic group is low, and therefore, it is difficult to prepare an aqueous dispersion of the polymer compound, or it is difficult to mix the aqueous coating liquid and the polymer compound used for forming the ink receiving layer. have. When content of compound (iii) exceeds 18.5% by molar ratio, the glossiness or printing density of the inkjet recording medium containing a polymer compound may fall.

When content of the compound (iii) in a polymer compound is in the said range, the quantity of a compound (iii) unit can occupy 3 mass% or more and 80 mass% or less of a polymer compound. When content is out of the said range, the functional fall of a polymer compound may be caused.

When content of the compound (iii) in a polymer compound exists in the said range, it is preferable that the quantity of the compound (i) unit to mix | blend occupies 10 mass% or more and 65 mass% or less of a polymer compound, and occupies 30 mass% or more and 65 mass% It is more preferable. When the amount of the compound (i) unit is less than 10% by mass, the effect of the polymer compound may be insufficient. When the amount of the compound (i) unit exceeds 65% by mass, the content of the hydrophilic group is low, and thus it may be disadvantageous to prepare an aqueous dispersion of the polymer compound.

Compound (ii) has a function of linking compound (i) and compound (iii) together. The amount of the compound (ii) to be used is not particularly limited. When content of compound (iii) is in the said range, it is preferable that the quantity of a compound (ii) unit occupies 10 mass% or more and 80 mass% or less, and it is more preferable to occupy 30 mass% or more and 60 mass% or less. . If the amount of the compound (ii) unit is within the above range, the compound (i) unit and the compound (iii) unit may be linked in an amount sufficient to exert their function.

The method for synthesizing the polymer compound from the compounds (i) to (iii) may be a one shot method or a prepolymer method. In the one shot method, the compounds (i) to (iii) are polymerized together in a random polymer. In the prepolymer method, compound (i) (or compound (iii)) and compound (ii) are reacted under isocyanate group rich conditions to synthesize a prepolymer having an isocyanate group at the terminal, followed by compound (iii) (or compound ( react with i)). In both methods, chain extenders such as low molecular weight polyols or diamines can be used. The molecular weight of the polymer compound can be adjusted by changing the amount of the compounds (i) to (iii) or by adding a reaction terminator such as monoalcohol or monoamine to the reaction system.

It is preferable that it is 2,000 or more and 150,000 or less, and, as for the weight average molecular weight of a polymer compound, it is more preferable that it is 2,000 or more and 50,000 or less. If the weight average molecular weight of a polymer compound is less than 2,000, glossiness or printing concentration may become low. When the weight average molecular weight of a polymer compound exceeds 150,000, reaction time becomes long and synthesis cost increases, which is unpreferable.

In the synthesis of the polymer compound, compounds containing two or more active hydrogen atoms (hereinafter referred to as "compound (iv)") other than the compounds (i) and (iii) may be copolymerized as necessary. Examples of compound (iv) include polyester polyols, polyether polyols and polycarbonate polyols, which may be used alone or in combination.

Examples of polyester polyols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol , Neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol of molecular weight 300 to 1,000, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexane dimethanol, bisphenol Glycol components such as A, bisphenol S, hydrogenated bisphenol A, hydroquinone and alkylene oxide adducts may be selected from malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, hen Decanedicarboxylic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxyl Acid, 2,5-naphthalenedicarboxylic acid, 2,6- Phthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bisphenoxyethane-p, p'-dicarboxylic acid, dicarboxylic anhydride, and ester-forming derivatives Polyester obtained by dehydration and condensation with acid; polyester obtained by ring-opening polymerization of cyclic esters such as ε-caprolactone; And polyesters obtained by copolymerizing these compounds.

Examples of the polyether polyol include one or more monomers such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran and cyclohexylene, and ethylene glycol and diethylene glycol. , Triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, glycerin, trimethylolethane, trimethylol Propane, sorbitol, sucrose, bisphenol A, bisphenol S, hydrogenated bisphenol A, aconitic acid, trimellitic acid, hemitic acid, phosphoric acid, ethylene diamine, diethylene triamine, triisopropanolamine, pyrogallol, dihydroxybenzoic acid And addition polymerization according to a conventional method, using a compound containing at least two active hydrogen atoms, such as hydroxyphthalic acid or 1,2,3-propanetriol as an initiator, as an initiator. The obtained product is mentioned. As another example of the polyether polyol, one or more monomers such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran and cyclohexylene may be used as ethylene diamine or propylene diamine. The product obtained by addition-polymerizing according to a conventional method is mentioned using the compound containing at least 2 primary amino groups, such as these as an initiator. In particular, polyethylene glycol is preferable.

As an example of a polycarbonate polyol, the compound obtained by reaction of glycol, such as 1, 4- butanediol, 1, 6- hexanediol, and diethylene glycol, and diphenyl carbonate and phosgene is mentioned.

Regarding the polymer compound, it is preferable to use a tin catalyst and / or an amine catalyst in the isocyanate polyaddition reaction. Examples of tin catalysts include dibutyltin dilaurate and stenus octoate. Examples of the amine catalyst include, but are not limited to, triethylene diamine, triethylamine, tetramethylpropane diamine, tetramethylbutane diamine, and N-methylmorpholine.

The isocyanate polyaddition reaction can be carried out in the absence of any solvent depending on the composition. However, for the purpose of suppressing the reaction of the reaction system and for the purpose of controlling the viscosity of the base, it is common to use a hydrophilic organic solvent which does not participate in the isocyanate polyaddition reaction as the reaction solvent. Examples of the hydrophilic organic solvent include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and diisobutyl ketone; Organic acid esters such as methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate and butyl propionate; And amines such as N, N'-dimethylformamide and N-methylpyrrolidone. The hydrophilic organic solvent used is preferably finally removed.

The polymeric compound can be stably dispersed or dissolved in water in such a manner that at least one portion of the compound (iii) unit is cationicized with an acid. When the compound (iii) is cationicized with a quaternizing agent such as an alkyl halide, the polymer compound cannot be stably dispersed in water in the form of particles of a desired size or can not be dissolved in water. The acid used herein is not particularly limited, and phosphoric acid and / or monovalent acid are preferred because the use of a polyacid may cause thickening when the polymer compound is dispersed or dissolved in water. For example, phosphorous acid may be used instead of phosphoric acid. Examples of monovalent acids 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. These acids are converted to acid anions by cationizing the compound (iii) unit. When the ink receiving layer of the inkjet recording medium is formed using a polymer compound cationicized with hydroxy acid, yellowing of the non-printing portion (blank portion) is suppressed as compared with the case of using a polymer compound cationicly catalyzed with another acid. Therefore, it is preferable to use a polymer compound cationized with hydroxy acid.

Preferred examples of the polymer compound obtained as described above are those represented by the formulas (1) to (6).

Content of the polymer compound in an ink receiving layer is 0.5 mass part or more and 8 mass parts or less per 100 mass parts of alumina pigments. It is preferable that especially content of the polymer compound in an ink receiving layer is 2 mass parts or more and 4 mass parts or less per 100 mass parts of alumina pigments.

In the ink receiving layer, when the mass part of the polymer compound per 100 parts by mass of the alumina pigment is represented by A, and the mass part of the water-soluble zirconium compound per 100 parts by mass of the alumina pigment is represented by B, the ratio B / A is 0.02 or more and 6 or less. If the ratio B / A is less than 0.02, the effect of scratch resistance is low. When ratio B / A exceeds 6, the ink receiving layer may crack (crack at the time of bending) at the time of conveyance. Therefore, it is preferable that ratio B / A is 0.1 or more and 1.5 or less, and it is more preferable that it is 0.15 or more and 0.2 or less.

It is preferable that the average particle size of the dispersion liquid prepared by disperse | distributing a polymer compound to an aqueous medium is 5 nm or more and 500 nm or less from a viewpoint of storage stability. In order to stably exist in the alumina dispersion liquid containing a water-soluble zirconium compound, and to improve the ink absorption of an inkjet recording medium, it is preferable that the average particle size of a dispersion liquid is more than 50 nm and 200 nm or less. As used herein, the average particle size is measured by dynamic light scattering method, and can be easily measured using, for example, Natrac UPA-150EX sold by Nikkkiso Co., Ltd.

It is preferable that the glass transition temperature (Tg) of a polymer compound is 50 degreeC or more and 80 degrees C or less. The glass transition temperature can be easily measured by differential scanning calorimetry (DSC). When the polymer compound and the water-soluble zirconium compound coexist, the polymer compound and the water-soluble zirconium compound coagulate appropriately in the drying step during the manufacturing process of the inkjet recording medium to form voids. If the glass transition temperature of the polymer compound is 50 ° C. or more and 80 ° C. or less, the polymer compound is supposed to interact with the water-soluble zirconium compound to form voids and form a film by drying while the polymer compound is in particle form. As a result, an inkjet recording medium having a pore structure excellent in ink absorption at high printing speed is obtained. If the glass transition temperature is lower than 50 ° C., since a film is formed before or immediately after drying, no voids are formed, and thus the effect of improving ink absorbency is low. When glass transition temperature is higher than 80 degreeC, particle | grains remain after a drying process and it may be difficult to obtain a transparent film.

Content of the polymer compound in an ink receiving layer is 0.5 mass part or more and 8 mass parts or less per 100 mass parts of alumina pigments. If the content is less than 0.5 parts by mass, the ink absorbency of the ink receiving layer is insufficient. When content exceeds 8 mass parts, the coloring property of an ink receiving layer is low. As for content, it is more preferable that they are 2 mass parts or more and 4 mass parts or less.

(additive)

The inkjet recording medium may contain additives such as pH adjusters, pigment dispersants, thickeners, fluidity enhancing agents, antifoaming agents, foaming inhibitors, surfactants, mold release agents, penetrants, colored pigments or colored dyes. The inkjet recording medium may also contain a fluorescent brightener, an ultraviolet absorber, an antiseptic, an antifungal agent, a water resistant additive, a dye fixer, a curing agent, a weathering material, and the like.

<Examples>

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. This invention is not limited to this Example or a comparative example. All parts and percentages below are on a mass basis unless otherwise specified.

<Synthesis of Polymer Compound 1-1>

Polymer compound 1-1 was synthesized as follows. Into a reaction vessel equipped with a stirrer, a thermometer and a reflux condenser, 140 g of acetone was added as a reaction solvent, and 50.00 g of 3,6-dithia-1,8-octanediol and 10.46 g of methyl diethanolamine were agitated by stirring. Dissolved in. The reaction vessel was heated to 40 ° C. and then 79.66 g of isophorone diisocyanate was added thereto. After the reaction vessel was heated to 50 ° C., 0.4 g of tin catalyst was added thereto. The reaction vessel was heated to 55 ° C. and the reaction was carried out for 4 hours under stirring.

After the reaction was completed, the reaction mixture was cooled to room temperature. 9.14 g of 35% hydrochloric acid was added to the reaction mixture for cationization. 573 g of water was added to the obtained reaction mixture. Acetone was removed from the reaction mixture by vacuum concentration. By adjusting the concentration of the residue with water, an aqueous dispersion of Polymer Compound 1-1 having a solid content of 20% was prepared. After diluting the aqueous dispersion with 1% water, the average particle size was measured using UPA-150EX. As a result, the average particle size was 35 nm. It was 60 degreeC when the glass transition temperature (Tg) of the polymer compound 1-1 was measured.

<Synthesis of Polymer Compound 1-2>

Polymer compound 1-2 was synthesized in substantially the same manner as used in the synthesis of polymer compound 1-1, except that 55.00 g of 3,6-dithia-1,8-octanediol was used. Furthermore, the aqueous dispersion of the polymer compound 1-2 of 20% of solid content was produced. The average particle size of this aqueous dispersion was 54 nm. The glass transition temperature of polymer compound 1-2 was 64 degreeC.

<Synthesis of Polymer Compound 1-3>

Polymer compound 1-3 was synthesized in substantially the same manner as used in the synthesis of polymer compound 1-1, except that 48.00 g of 3,6-dithia-1,8-octanediol was used. Furthermore, the aqueous dispersion of the polymer compound 1-3 of 20% of solid content was produced. The average particle size of this aqueous dispersion was 96 nm. The glass transition temperature of polymer compound 1-3 was 60 degreeC.

Synthesis of Polymer Compound 1-4

Polymer compound 1-4 was synthesized in substantially the same manner as used in the synthesis of polymer compound 1-1, except that 53.00 g of 3,6-dithia-1,8-octanediol was used. In addition, an aqueous dispersion of Polymer Compound 1-4 having a solid content of 20% was prepared. The average particle size of this aqueous dispersion was 155 nm. The glass transition temperature of polymer compound 1-4 was 64 degreeC.

<Production of Supports>

The stock containing the following component was manufactured.

100 parts by mass of pulp slurry

80 parts by mass of hardwood bleached kraft pulp (LBKP) in Yeosu-do 450 ml CSF (Canadian Standard Freeness)

20 parts by mass of conifer bleaching kraft pulp (NBKP) of Yeosu 480 ml CSF

0.60 parts by mass of cationic starch

10 parts by mass of heavy calcium carbonate

15 parts by mass of hard calcium carbonate

0.10 parts by mass of alkyl ketene dimer

0.03 parts by mass of cationic polyacrylamide.

This stock was papered using a long paper machine. The paper was wet pressed in three steps and then dried in a multi-dry dryer. The obtained paper was impregnated with an aqueous solution of oxidized starch so that the solid content was 1.0 g / m ² using a size press, and then dried. The machine was obtained by machine calendering the obtained paper. The base had a basis weight of 170 g / m ² , a Stockigt size of 100 seconds, an air permeability of 50 seconds, a Beck smoothness of 30 seconds, and a Gurley strength of 11.0 mN.

The following composition was applied to the matrix in an amount of 25 g / m ² : A polymer composition containing 70 parts by mass of low density polyethylene, 20 parts by mass of high density polyethylene and 10 parts by mass of titanium oxide. Moreover, the polymer coating support body was manufactured by apply | coating the polymer composition containing 50 mass parts of high density polyethylene and 50 mass parts of low density polyethylene to the known back surface in the quantity of 25 g / m <^2> .

Preparation of Alumina Hydrate Dispersion

The following compound was mixed with 213 g of pure water: 100 g of alumina pigment 1 and 1.5 g of pelic acid. Alumina pigment 1 was alumina hydrate disperal HP14 available from Sasol. Haegyo acid was methanesulfonic acid. The usage-amount of peptizing acid was 1.5 mass parts per 100 mass parts of alumina pigments 1. Alumina hydrate dispersion 1 was prepared by stirring the mixture with a mixer for 30 minutes. By the substantially same method as above, the alumina dispersion liquid 2-31 was prepared. In the preparation of the alumina dispersions 2 to 31, the following acids were used instead of methanesulfonic acid as pebris acid: ethanesulfonic acid, butanesulfonic acid, acetic acid, amidosulfuric acid or benzenesulfonic acid. When alumina pigment 2 was used in addition to alumina pigment 1, alumina pigments 1 and 2 were mixed together in a powder state, and the alumina hydrate was prepared by substantially the same method as that used for the preparation of alumina hydrate dispersion 1. Alumina Pigment 2 was Alu-C (formerly Aluminum Oxide C) available from Degussa.

(Example 1)

Polyvinyl alcohol was melt | dissolved in ion-exchange water, and the polyvinyl alcohol aqueous solution of 9.0 mass% of solid content was obtained. The polyvinyl alcohol used was PVA 235 with a weight average degree of polymerization of 3,500 and a degree of saponification of 88% available from Kuraray Co., Ltd .. When the solid content of the polyvinyl alcohol aqueous solution was X and the solid content of the alumina hydrate dispersion 1 was Y, the polyvinyl alcohol aqueous solution was mixed with the alumina hydrate dispersion 1 so that the formula (X / Y) × 100 = 9%. This mixture and zirconium acetate, boric acid, and the polymer compound 1-1 were mixed by the quantity shown in Table 1, and the coating liquid for ink receiving layer formation was obtained.

This coating solution was applied to the support in an amount of 35 g / m ² using a slide die. The temperature of the coating liquid was 45 degreeC. Inkjet recording medium 1 was prepared by drying the coated support at 80 ° C.

(Examples 2 to 19 and Comparative Examples 1 to 10)

An inkjet recording medium was prepared in substantially the same manner as described in Example 1, using the alumina pigment 1, the alumina pigment 2, the bridged acid, the crosslinking agent 1, the crosslinking agent 2 and the polymer compound as shown in Table 1. Alumina pigment 1 was disperal HP14 available from Sazole. Alumina pigment 2 was Alu-C (formerly aluminum oxide C) commercially available from Degussa.

In Comparative Examples 9 and 10, an inkjet recording medium was produced using a cationic urethane compound instead of the polymer compound. The cationic urethane compound used is SUPERFLEX 620 (SF 620) (average particle size 30 nm, glass transition temperature 43 DEG C), commercially available from Dai-ichi Kogyo Seiyaku Co., Ltd. And Superflex 640 (SF 640) (average particle size 15 nm, glass transition temperature -17 ° C) sold by Daiichi Kogyo Seiyaku Co., Ltd.

<Table 1-1>

<Table 1-2>

<Evaluation>

Hereinafter, the evaluation method of the inkjet recording medium is demonstrated.

<Evaluation 1: Bk O. D. Value>

The Bk O. D. values of the inkjet recording media 1 to 31 prepared as above were measured. Specifically, using a recording unit iP 4600 commercially available from Canon KABUSHIKI KAISHA, the black solid pattern of the RGB values (0, 0, 0) is printed and inkjet recording media 1 to 31 are printed for 1 day. After standing, color was measured using Gretag Spectrolino, available from Gretag Macbeth. The measurement results are shown in Table 1.

<Evaluation 2: Moisture Resistance>

The moisture resistance of the inkjet recording media 1 to 31 prepared as described above was evaluated. Specifically, using a recording unit iP 4600 commercially available from Canon Corporation, printing a blue solid image on each inkjet recording medium 1 to 31, and a white missing character "Den-kyo (Japanese)" on the blue solid image. Were printed at 48 points and 10 points, and the inkjet recording media 1 to 31 were left for 14 days in a 30 ° C atmosphere of 90% relative humidity. The bleeding of the color material to white missing characters before and after leaving the inkjet recording media 1 to 31 in the above atmosphere was visually inspected. Inkjet recording media 1 to 31 were evaluated according to the following criteria.

Rank 5: White missing characters printed at 10 and 48 points have no bleeding at all and are very good.

Rank 4: White missing characters printed with 10 points have bleeding, while white missing characters printed with 48 points have no bleeding at all.

Rank 3: White missing characters, printed at 10 and 48 points, have bleeding but not bleeding overall.

Rank 2: White missing characters printed at 10 points are bleeding entirely, and white missing characters printed at 48 points are not bleeding entirely.

Rank 1: White missing characters printed at 10 and 48 points are bleeding overall.

<Evaluation 3: ink absorbency>

The ink absorbency at the time of high speed printing of the inkjet recording media 1-31 manufactured as mentioned above was evaluated. The recording unit used was a modification of the printing method of the Pro 9000 commercially available from Canon Corporation. The printing method used was a one-way printing in which printing was completed in one pass at a carriage speed of 15 inches / second. The printing pattern used had three colors of cyan, yellow, and green, and was able to determine boundary bleeding (so-called bleeding), and the pattern of ink application was variable. The maximum amount of ink applied was set at 160% duty and varied at 10% duty intervals. Printing was performed in a high humidity atmosphere with a temperature of 30 ° C. and a relative humidity of 80%. As used herein, the term "100% duty" means giving 22 ng of ink to a 600 dpi square area. Inkjet recording media 1 to 31 were visually evaluated according to the following criteria.

Rank 5: Beading does not occur even at 160% duty.

Rank 4: Beading occurs at 160% duty, but no bidding is observed at 150% duty.

Rank 3: Beading occurs at 150% duty, but no bidding is observed at 130% duty.

Rank 2: Beading occurs at 130% duty, but no bidding is observed at 120% duty.

Rank 1: Beading occurs at 100% duty.

<Evaluation 4: crack at the time of conveyance>

The crack of the ink receiving layer at the time of conveyance was evaluated by the method of fast-printing the inkjet recording media 1-31 manufactured as mentioned above. As used herein, the term "cracking of the ink receiving layer at the time of conveyance" means that the ink receiving layer is cracked at the time of u-turn conveyance of the sheet or conveyance of the roll paper. The evaluation method is as follows: when the metal rollers of various diameters are pressed against the ink jet recording medium and the ink jet recording medium is bent at a curved surface corresponding to the diameter of one of the metal rollers, the ink jet recording medium is cracked or not. The medium was evaluated. Inkjet recording media 1 to 31 were visually evaluated according to the following criteria.

Rank 5: No cracking even at 8 mm diameter.

Rank 4: No crack occurs at 12 mm diameter, but crack occurs at 8 mm diameter.

Rank 3: Cracks do not occur at a diameter of 20 mm, but cracks occur at a diameter of 12 mm.

Rank 2: A crack does not occur at a diameter of 25 mm, but a crack occurs at a diameter of 20 mm.

Rank 1: Cracks in diameter 25 mm.

<Evaluation 5: scratch resistance at the time of return>

The surface scratches at the time of conveyance of the inkjet recording media 1-31 manufactured as mentioned above were evaluated by the method of high speed printing of the inkjet recording media 1-31. As used herein, the term "surface abrasion at the time of conveyance" refers to a hard member such as a roller that supports the ink receptive layer at the time of conveyance and the ink receptive layer to be contacted, and the glossiness of the contact portion of the ink receptive layer changes, which is recognized as a scratch. Means that. The evaluation unit used was a modification of the Pro 9000 commercially available from Canon Corp. The black solid print was visually evaluated for the scratches according to the following criteria. Visual evaluation was conducted in two environments: the office environment (environment 1) and the sunny environment outdoors (environment 2). In outdoor environments, scratches were very noticeable due to strong sunlight.

Rank 5: No scratches at all in Environment 1 or 2.

Rank 4: Scratch is not noticeable at all in Environment 1, but slightly noticeable in Environment 2.

Rank 3: Slightly noticeable scratches in Environments 1 and 2.

Rank 2: Slightly noticeable scratches in Environment 1, very noticeable in Environment 2.

Rank 1: Scratch very prominent in Environments 1 and 2.

Table 2 shows the evaluation results of Examples 1 to 21 and Comparative Examples 1 to 10.

<Table 2>

As apparent from the results shown in Table 2, in the present Example, the value of O. D. was large, and rank 3 or more was obtained in evaluation of moisture resistance, ink absorption, crack resistance, and scratch resistance. In the comparative example, the O. D. value is relatively small, and rank 2 or less is obtained by evaluation of any one of moisture resistance, ink absorption, crack resistance, and scratch resistance. From this, it can be seen that color development, moisture resistance, ink absorption, crack resistance and scratch resistance can be achieved by the configuration according to the present invention.

While the invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The following claims are to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims (6)

A support; And
An inkjet recording medium provided on the support and including an ink receiving layer containing an alumina pigment, an alkylsulfonic acid having 1 to 4 carbon atoms, a polymer compound, a water-soluble zirconium compound, and boric acid or a borate salt,
The ink receiving layer is 0.5 parts by mass to 8 parts by mass of the polymer compound, 0.15 parts by mass to 3 parts by mass of the water-soluble zirconium compound, and 0.8 parts by mass to 3 parts by mass of the boric acid or borate, per 100 parts by mass of the alumina pigment. Contains; The polymer compound includes (i) a sulfur-containing organic compound containing two or more active hydrogen atoms, (ii) a polyisocyanate compound containing two or more isocyanate groups, and (iii) an amine containing two or more active hydrogen atoms. At least one amino group of the product obtained by the reaction of at least three compounds of the compound is obtained by cationating with an acid; The inkjet recording medium whose ratio B / A is 0.02-6 when the mass part of the said polymer compound is represented by A per 100 mass parts of alumina pigments, and the mass part of the said water-soluble zirconium compound per 100 mass parts of alumina pigments. The inkjet recording medium according to claim 1, wherein the polymer compound has a weight average molecular weight of 2,000 to 150,000 and is at least one selected from the group consisting of compounds represented by the following formulas (1) to (6).
&Lt; Formula 1 >

In the formula, n represents 1 or 2, R ₁ represents a methylene group, an ethylene group or a propylene group, R ₉ represents an alkylene group or an aliphatic hydrocarbon group containing one or more polyalicyclic groups, and R ₁₀ represents 1 carbon atom. Or more represent 4 or less alkyl groups, R ₁₁ and R ₁₂ independently represent a hydrogen atom or a methyl group, and X ⁻ represents an acid anion.
(2)

Wherein n represents 1 or 2, R ₂ and R ₃ independently represent a hydrogen atom, a hydroxyl group or an alkyl group, may be the same or different from each other, and R ₉ is an alkylene group or one or more polyalicyclic rings An aliphatic hydrocarbon group containing a group group is represented, R ₁₀ represents an alkyl group having 1 to 4 carbon atoms, R ₁₁ and R ₁₂ independently represent a hydrogen atom or a methyl group, and X ⁻ represents an acid anion.
(3)

In the formula, n represents 0 or 1, R ₉ represents an alkylene group or an aliphatic hydrocarbon group containing one or more polyalicyclic groups, R ₁₀ represents an alkyl group having 1 to 4 carbon atoms, R ₁₁ and R ₁₂ Independently represents a hydrogen atom or a methyl group, and X ⁻ represents an acid anion.
&Lt; Formula 4 >

In the formula, n represents 1 or 2, R ₄ represents a sulfur atom or an oxygen atom, R ₅ represents a sulfur atom or a sulfonyl group, R ₄ and R ₅ are different from each other, R ₉ is an alkylene group, or An aliphatic hydrocarbon group containing at least one polyalicyclic group is represented, R ₁₀ represents an alkyl group having 1 to 4 carbon atoms, R ₁₁ and R ₁₂ independently represent a hydrogen atom or a methyl group, and X ⁻ represents an acid anion.
&Lt; Formula 5 >

Wherein R ₆ and R ₇ independently represent a hydrogen atom or a methyl group, may be the same or different from each other, R ₉ represents an alkylene group, or an aliphatic hydrocarbon group containing at least one polyalicyclic group, and R ₁₀ is An alkyl group having 1 to 4 carbon atoms, R ₁₁ and R ₁₂ independently represent a hydrogen atom or a methyl group, and X ⁻ represents an acid anion.
(6)

In the formula, R ₈ represents a hydroxyl group or an alkyl group, R ₉ represents an alkylene group or an aliphatic hydrocarbon group containing one or more polyalicyclic groups, R ₁₀ represents an alkyl group having 1 to 4 carbon atoms, R ₁₁ And R ₁₂ independently represent a hydrogen atom or a methyl group, and X ⁻ represents an acid anion. The inkjet recording medium of claim 1, wherein the alkylsulfonic acid is methanesulfonic acid. The inkjet recording medium according to claim 1, wherein the alumina pigment contains alumina hydrate or alumina hydrate and vapor phase alumina, and the mass ratio of the alumina hydrate to vapor phase alumina is 100: 0 to 70:30. The inkjet recording medium according to claim 1, wherein the ratio B / A is 0.15 or more and 1.5 or less. An inkjet recording medium according to claim 1, wherein the water soluble zirconium compound is zirconium acetate.