JPH09267544A - Paper for ink-jet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a paper for recording without generating discoloration or discoloration of coloring matters and with excellent light resistance by incorporating a compd. of a specified formula in an ink receiving layer provided in a substrate or on the substrate. SOLUTION: A compd. of a formula HO-N(R1 )(R2 ) wherein R1 and R2 are independently a hydrogen atom, an alkyl group, an alkoxy group, a carbamoyl group, an alkoxycarbonyl group or an acyl group is incorporated in a receiving layer provided in or on a substrate. The alkyl group expressed by R1 and R2 in the formula is a 1-18C linear, branched or cyclic alkyl group and may have respectively a substituted atom or a substituted group. As the substituted atom or the substituted group, e.g. alkoxy group, aryl group, heterocyclic group, alkoxycarbonyl group, carbamoyl group, acyl group, alkenyl group, hydroxyl group, halogen atom, cyano group, nitro group, amino group, phosphono group or phosphine group, etc., are cited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording sheet for recording using an aqueous ink, and more particularly to an inkjet recording sheet with improved light resistance.

[0002]

2. Description of the Related Art The ink jet recording system is one in which minute droplets of ink are ejected by various operating principles and adhered to a recording sheet such as paper to record an image / character, but at a relatively high speed. It has advantages such as low noise and easy multicoloring. With regard to nozzle clogging and maintenance, which have been a problem with this system, improvements have been made in terms of both ink and equipment, and are now rapidly spreading to various fields such as various printers, facsimiles, and computer terminals. .

As a recording paper used in this ink jet recording system, the density of print dots is high, the color tone is bright and vivid, the ink is absorbed quickly, and the ink flows out even when the print dots overlap. It is required that the ink does not bleed, that the diffusion of the print dots in the lateral direction is not excessively large, and that the periphery is smooth and does not blur.

In order to solve these problems, for example,
Japanese Unexamined Patent Publication No. 52-53012 discloses an inkjet recording paper obtained by wetting a low-sized base paper with a paint for surface treatment. Further, JP-A-55-5830 discloses an ink jet recording paper having an ink-absorbent coating layer on the surface of a support, and JP-A-55-5158.
No. 3 and JP-A-56-157 disclose examples in which non-colloidal silica powder is used as a pigment in a shoe layer.

However, in general, when the ink-receptive ink-receptive layer is composed only of a layer having many voids for absorbing and holding ink, the ink-receptive layer having many voids forms an interface with the air. Since the surface of the coating film has many micro irregularities, the incident light to the ink receiving layer is scattered and the transmission thereof is blocked, so that it becomes difficult to produce gloss and becomes opaque. Furthermore, since it is difficult for light to reach the ink that has penetrated into the voids, the image becomes whitish and the color reproducibility and color density are reduced. While maintaining sex
It was difficult to obtain an image with high color reproducibility and color density.

On the other hand, for the purpose of imparting gloss and other purposes, a hydrophilic binder such as gelatin or polyvinyl alcohol, which absorbs ink due to dissolution or swelling of the ink absorbing layer when the ink droplets land, is coated on the support. A large number of recording papers, films and the like have been conventionally known.

For such an ink jet recording paper, various methods have been conventionally proposed in order to improve the durability of a printed image against light.

For example, JP-A-57-74193 and JP-A-5-74193.
Nos. 7-87988 and 62-261478 describe inkjet recording papers containing an ultraviolet absorber. It is certainly effective to protect the recorded image from UV irradiation and improve the light resistance of the image by incorporating the UV absorber.

However, the color fading of the dye upon light irradiation is mostly caused not only by the ultraviolet region but also by the light in the light absorbing region of the visible region. For the dye that fades due to the absorption of light, the effect of improvement by the ultraviolet absorber is small.

Further, the ultraviolet absorber naturally has a small effect unless it is present on the light irradiation side of the recorded dye image, but in the case where the dye diffuses and permeates only in the vicinity of the surface when ink jet recording is performed. The anti-fading effect of the ultraviolet absorber is often small.

In addition to the ultraviolet absorber, various methods have been proposed to prevent photobleaching, and a method for preventing discoloration with an antioxidant is also known in ink jet recording.

For example, JP-A-57-74192 and 57.
-87989, 60-72785, 61-14.
No. 6591, No. 62-170381, No. 62-614.
77 and JP-A-3-13376.

However, none of the conventionally known antioxidants or anti-fading agents have an insufficient anti-fading effect, or even if they have an anti-fading effect, they themselves are colored or the recording dye is discolored. There are many things that have a bad effect such as being damaged.

Particularly, the magenta dye image has a strong tendency to undergo photobleaching more easily than other colors, and its improvement is desired.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an ink jet recording medium which does not cause discoloration of an ink jet recording sheet or discoloration of a dye and which is excellent in light resistance. To provide recording paper.

[0016]

The above object of the present invention is attained by the following constitutions.

1. An ink jet recording paper, comprising a compound represented by the following general formula (1) in a support or in an ink receiving layer provided on the support.

In the general formula (1) HO—N (R ₁ ) (R ₂ ), R ₁ and R ₂ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a carbamoyl group, an alkoxycarbonyl group or an acyl group. Represent

2. The inkjet recording paper is an inkjet recording paper having a hydrophilic binder layer on a support, and the hydrophilic binder layer is represented by the general formula (1).
A compound represented by the formula:
2. The ink jet recording paper according to item 1.

The present invention will be described in detail below.

The alkyl group represented by R ₁ and R ₂ in the general formula (1) is a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, each having a substituent atom and a substituent. It may be. Examples of the substituent atom and the substituent include an alkoxy group, an aryl group, a heterocyclic group, an alkoxycarbonyl group, a carbamoyl group, an acyl group, an alkenyl group, a hydroxyl group, a halogen atom, a cyano group, a nitro group, an amino group, a sulfo group, Carboxy group, sulfamoyl group,
Examples thereof include ureido group, phosphono group, phosphine stomach and the like.

The alkoxy group represented by R ₁ and R ₂ in the general formula (1) is a linear or branched alkoxy group having 1 to 8 carbon atoms and may have a substituent. Examples of the substituent include the substituent that can be possessed when R ₁ and R ₂ are alkyl groups.

The carbamoyl group represented by R ₁ and R ₂ in the general formula (1) is, for example, a methylcarbamoyl group or an ethylcarbamoyl group, which may have a substituent.

The substituent is appropriately selected from the substituents that can be possessed when R ₁ and R ₂ are alkyl groups.

The alkoxycarbonyl group represented by R ₁ and R ₂ in the general formula (1) is, for example, a methoxycarbonyl group or an ethoxycarbonyl group, and may have a substituent. The substituent is appropriately selected from the substituents that can be possessed when R ₁ and R ₂ are alkyl groups.

The acyl group represented by R ₁ and R ₂ in the general formula (1) includes, for example, an acetyl group, a propanoyl group, a benzoyl group and the like and may have a substituent. The substituent is appropriately selected from the substituents that can be possessed when R ₁ and R ₂ are alkyl groups.

Among the compounds represented by the general formula (1),
Particularly, it is preferable that R ₁ and R ₂ are each independently a substituted or unsubstituted alkyl group, but particularly, a sulfo group, a carboxyl group,
Those having a hydrophilic group such as a hydroxyl group or a sulfonamide group as a substituent and having a solubility in water of 1% by weight or more at room temperature are particularly preferable (eg, sulfoethyl group, sulfopropyl group, carboxyethyl group, carboxymethyl group). , Carboxypropyl groups, etc.).

The compound having a hydrophilic group has not only a large improvement in light resistance, but also a sufficient light resistance improving effect can be obtained even when the recording paper is stored at high temperature for a long time before printing.

Specific examples of the compound represented by the general formula (1) are shown below.

[0030]

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[0031]

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[0032]

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Some of the compounds represented by the above general formula (1) are commercially available, but in many cases, the corresponding hydroxylamines are alkylated with an appropriate alkylating agent or acylated with an acylating agent. And can be easily synthesized by, for example, West German Patent 1,159,634 or "Inorganica Chemica Actor" (Inorgan).
ica Chimica Acta), 93 (198)
4) It can be easily synthesized according to the synthesis method described in 101 to 107 and the like.

[0034] The amount of the general formula (1) compound represented by the addition to the ink-jet recording sheet varies depending on the form to be added, in general, an ink jet recording paper 1 m ² per usually 0 In the case of adding in the paper support. It is 01 to 20 g, more preferably 0.1 to 2 g.

When it is added to any hydrophilic binder layer on the support, the ink jet recording paper 1 m
^It is preferably 0.02 to 5 g per ² and more preferably 0.05 g to 1 g.

The ink jet recording paper of the present invention is an ink jet recording paper having an ink receiving layer on a paper or a support.

The latter case in which the effect of the present invention is particularly large will be described below.

The support used in the ink jet recording paper of the present invention is paper, a paper support in which both sides of the paper are coated with a hydrophobic resin such as polyethylene, and an art in which a white pigment and a hydrophilic binder are coated on the surface of the paper. Various coated papers such as paper and cast coated paper, cloths, synthetic resin supports such as polyethylene terephthalate, polyethylene phthalate and polystyrene, and supports such as glass can be used.

As the ink receiving layer coated on the above support, a hydrophilic binder layer is preferably provided. Such an ink receiving layer includes a layer made of a hydrophilic binder and a receiving layer containing various inorganic or organic fillers together with the hydrophilic binder.

The former ink receiving layer made of a hydrophilic binder is a layer for receiving the ink liquid by dissolving or swelling the hydrophilic binder during ink recording.

On the other hand, the hydrophilic binder layer containing an inorganic or organic filler has voids formed therein.
The ink liquid is retained by the effect of the swelling or dissolution of the voids and the hydrophilic binder.

As the hydrophilic binder used in the above various ink receiving layers, gelatin or gelatin derivative,
Polyvinylpyrrolidone, pullulan, polyvinyl alcohol or its derivatives, carboxymethyl cellulose, hydroxyethyl cellulose, dextran, dextrin, polyacrylic acid and its salts, agar, κ-carrageenan, λ-carrageenan, ι-carrageenan, xanthene gum, locust bean gum, alginic acid. , Gum arabic, polyalkylene glycol (molecular weight of about 5000 or more), block copolymer of polyalkylene glycol described in JP-A-7-195826, water-soluble polyvinyl butyral, or JP-A-62-245260. Polymers such as a vinyl monomer having a carboxyl group or a sulfonic acid group, or a copolymer having these vinyl monomers repeated can be mentioned. These hydrophilic binders may be used alone or in combination of two or more.

However, from the viewpoint of coating, it is preferable to use at least one kind of hydrophilic binder capable of reversible sol-gel conversion. From this point, at least one kind of gelatin, gelatin derivative and κ-carrageenan is used. Preference is given to using.

Preferred polymers are those containing at least gelatin or a gelatin derivative, and further, a combination of gelatin or a gelatin derivative and polyvinylpyrrolidone, a combination of a gelatin derivative and polyvinyl alcohol and its derivative, a gelatin derivative, polyvinylpyrrolidone and polyvinyl. A combination with an alcohol, and further a combination of gelatin or a gelatin derivative and a polyalkylene glycol are particularly preferable.

When the hydrophilic binder layer comprises two or more layers, these may be a combination of hydrophilic binders of the same kind or a combination of different hydrophilic binders.

As the gelatin preferably used in the above, ordinary alkali-processed gelatin and acid-processed gelatin can be used. Usually, the isoelectric point of such gelatin can be appropriately selected and used in the range of 9 to 5.

Derivative gelatin is obtained by reacting the amino group or imino group of the above gelatin with an acid anhydride such as phthalic anhydride or an isocyanate such as phenyl isocyanate.
Gelatin in which at least a part of amino groups and imino groups are inactivated is preferable.

The polyvinyl alcohol preferably has an average degree of polymerization of 300 to 1000 and a degree of saponification of 70 to 95%.

Further, as the polyvinyl alcohol derivative, a conventionally known one for inkjet recording paper can be appropriately selected and used. Examples of such a polyvinyl alcohol derivative include, for example, JP-A 61-1048.
No. 3, No. 61-27279, No. 61-134291 and JP-A-6-143798, cation-modified polyvinyl alcohol described in JP-A-6-155895, acetoacetylated polyvinyl alcohol described in JP-A-6-155895, JP-A-6-55743 The modified vinylpyrrolidone polyvinyl alcohol described in JP-A-7-101141 and the silyl-modified polyvinyl alcohol described in JP-A-7-101141 are used.

The total amount of the hydrophilic binder layer used in the ink jet recording paper of the present invention is usually 1 to 20 g, preferably 2 to 10 g.

The inkjet recording paper of the present invention preferably has at least two layers of an ink receiving layer containing a hydrophilic binder.

The particularly preferable ink jet recording paper of the present invention has at least two hydrophilic binder layers on the recording surface side of the support. The hydrophilic binder layers include a protective layer, an inorganic pigment containing layer and a polymer layer. Examples include a layer containing a text, a layer containing an ultraviolet absorber, a layer containing an image stabilizer, and a dye fixing layer. Each of these layers may be one in which two or more functions are performed by a single layer, or the layers which perform the same function may be divided into two or more layers.

The main purpose of the protective layer is to maintain the surface gloss and to provide a proper slipperiness and a sticking preventive function, and the characteristics and constitution thereof are particularly important in the ink jet recording paper of the present invention.

Therefore, it is not preferable to add a large amount of inorganic pigment, organic fine particles, oil droplets, or a material having high hygroscopicity, which deteriorates gloss. The content of the inorganic pigment or organic fine particles added to the protective layer is generally 10% by weight or less, preferably 2% by weight or less, with respect to the hydrophilic binder constituting the protective layer. Further, the oil droplets such as the emulsified dispersion and the like added to the protective layer are approximately 50% by weight or less, preferably 20% by weight or less with respect to the hydrophilic binder.

In the ink jet recording paper of the present invention, examples of the above-mentioned inorganic or organic filler for forming voids in the hydrophilic binder layer include inorganic pigments such as light calcium carbonate, heavy calcium carbonate, and the like. Magnesium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina , White colloidal alumina, pseudo-boehmite, aluminum hydroxide, lithopone, zeolite, hydrohaloisite, magnesium hydroxide and other white inorganic pigments, and organic fine particles such as styrene plastic pigment, acrylic plastic pigment, polyethylene Emissions, microcapsules, urea resins, melamine resins, and the like.

However, in order to maintain good glossiness, the particle size of the above-mentioned various fillers is usually 0.5 μm or less, preferably 0.2 μm or less, particularly preferably 0.0
It is preferable to use one having a thickness of 5 μm or less.

The above-mentioned filler is a hydrophilic binder,
Usually 0.5 to 50% by weight, preferably 1 to 30% by weight.
% By weight.

The film thickness of the filler-containing hydrophilic binder layer is generally 2 to 50 μm, preferably 5 to 40 μm, though it varies depending on the type of the support and the presence or absence of the filler-free hydrophilic binder layer.

There is no particular limitation on the amount of coating solid content on the ink recording surface side of the ink jet recording paper of the present invention,
Generally, 5 to 60 g / m ² is preferable, and 10 to 40 g / m ² is more preferable. Note that, from the viewpoint of preventing curl after forming a recorded image, it is preferable to form the recording image as thin as possible.

In order to prevent curling, the back side may contain a hydrophilic binder such as gelatin, a gelatin derivative, polyvinylpyrrolidone and polyvinyl alcohol, and a matting agent used as necessary.

The amount of the hydrophilic binder used on the back surface is preferably 1 to 10 g, and more preferably ^{2 to 8} g per 1 m ² of the ink jet recording paper. A preferred matting agent is silica fine powder having an average particle diameter of 2 to 20 μm.

Further, in the ink receiving layer of the present invention, if necessary, a UV absorber, an antioxidant other than the above general formula (1), a dispersant, a fluorescent dye, a pH adjusting agent, a defoaming agent, a lubricant are further added. Various known additives such as agents, preservatives, surfactants, thickeners, cross-linking agents, antistatic agents, matting agents and the like can be contained.

The ink jet recording paper of the present invention is preferably coated by the curtain coating method or US Pat.
An extrusion coating method using a hopper described in Japanese Patent No. 681,294 is preferably used.

At this time, it is preferable from the viewpoint of productivity that the coating liquid set in the drying step is heated under the condition that the coating liquid is not redissolved. Usually, after setting, after evaporating water to some extent within the range of room temperature to 30 ° C., it is heated to 40 ° C. to 50 ° C. and completely dried.

The set temperature is determined by the set temperature of each coating solution, but it is generally carried out by blowing cold air around 0 ° C.

[0066]

The present invention will be described below with reference to examples of the present invention.
The present invention is not limited to these examples. In addition,
In the examples, "%" indicates absolute dry weight% unless otherwise specified, and the addition amount indicates the amount per 1 m ^{2 of} inkjet recording paper.

Example 1 The back side of the recording surface of a paper support (thickness 140 μm, containing 7% by weight of anatase type titanium dioxide in the polyethylene layer on the recording surface side) of 100 g / m ² of base paper coated with polyethylene. 3. Alkali-treated gelatin as back layer
A coating liquid having the following layer structure was simultaneously coated on the support obtained by coating and drying at ² g / m ² .

First layer: Alkali-treated gelatin 1.0 g Surfactant-1 0.002 g Second layer: Alkali-treated gelatin 4.0 g Polyvinylpyrrolidone (K90) 4.0 g Surfactant-1 0.006 g Third layer : Phenylcarbamoylated gelatin 1.0 g Polyvinylpyrrolidone (K90) 1.0 g Surfactant-2 0.02 g Surfactant-3 0.12 g Coating was performed by simultaneous coating of three layers by a slide hopper coating method. . For coating, superimpose each coating solution at 35 ℃ and
After cooling set at ~ 5 ° C for about 20 seconds, 20-50 ° C
Ink jet recording paper-1 was obtained by rapid drying for 4 minutes with a wind in the range.

On the other hand, in the ink jet recording paper-1, ink jet recording papers- ² to 11 were prepared by adding 0.2 g of the additive of the present invention and the comparative additive shown in Table 1 to the second layer per 1 m2 of ink jet recording paper. Was prepared in the same manner as the inkjet recording paper-1. The structures of the surfactants and the comparative compounds used in Samples 9 to 11 are shown below.

[0070]

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[0071]

[Table 1]

A magenta image was printed on each of the obtained ink jet recording papers using an ink jet printer MJ-900 manufactured by Seiko Epson Corporation, and light resistance was evaluated by irradiating light with a xenon fade meter.

The light resistance was shown by the light irradiation time required for the point where the initial density was 1.0 to be -30%.

Further, contamination of a white background portion (ΔDb = density change by blue reflection density measurement) was measured by irradiation with a xenon fade meter for 300 hours. Table 2 shows the results.

[0075]

[Table 2]

From the results shown in Table 2, it can be seen that the samples of the present invention have improved light resistance without causing contamination of the white background.

On the other hand, Sample 9 using Comparative Compound R-1 showed a small improvement in light resistance, and Comparative Sample 1
It can be seen that 0 and 11 have a large improvement in light resistance, but have a large amount of white background contamination.

Example-2 Inkjet recording paper prepared in Example-1-1.
After storing 11 for 2 weeks at 55 degreeC, light resistance was evaluated like Example-1. The results are shown in Table 3.

[0079]

[Table 3]

From the results shown in Table 3, the comparative sample 1 containing no anti-fading agent has a small effect of improving the light resistance when stored at high temperature for a long time, but the samples (2-8) of the present invention have It can be seen that it has a good fading property. In particular, it can be seen that the recording paper containing S-1, S-4, S-11 and S-16 having a hydrophilic group has a high effect of preventing discoloration after storage and a small increase in contamination.

[0081]

As described above, when the constitution of the ink jet recording paper of the present invention is used as demonstrated in the embodiment, the ink jet recording paper satisfying the good light resistance of the dye can be obtained.

Claims (2)

[Claims] 1. An ink jet recording paper comprising a compound represented by the following general formula (1) in a support or in an ink receiving layer provided on the support. Formula (1) HO-N (R 1) (R 2) wherein each of R ₁ and R ₂ are independently a hydrogen atom, an alkyl group, an alkoxy group, a carbamoyl group, an alkoxycarbonyl group or an acyl group. ] 2. The inkjet recording paper is an inkjet recording paper having a hydrophilic binder layer on a support, and the hydrophilic binder layer contains the compound represented by the general formula (1). The inkjet recording paper according to claim 1.