JPH05131740A - Ink jet recording paper - Google Patents

Abstract

PURPOSE:To manufacture a high quality ink jet recording paper which is of superior ink receptivity, prevents set-off of ink n a rear face and is provided with extremely high opaque properties, superior ink drying characteristics, high image density and superior color developing properties and clarity. CONSTITUTION:A synthetic sizing agent contained in a base paper is prepared by turning a reactive composition composed of at least (a) an 8-34C hydrophobic monomer and (b) an amine compound containing amino into epoxy, and an ink receiving layer containing a water absorption polymer compound is formed on the base paper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of ink jet recording paper used in various types of equipment utilizing the ink jet recording method.

[0002]

2. Description of the Related Art Ink jet recording systems are used in various fields as various printers and plotters because they are low in noise, high-speed recording is possible, and multi-coloring is easy.

Recording media used in the ink jet recording system include high-quality paper, coated paper, synthetic paper, cloth, and the like.
Efforts have been made to improve recording devices and ink compositions so that sheets such as plastic films can be used.

However, at the present time, it has not been satisfactory yet. Further, the performance of the recording apparatus such as the higher speed and the higher definition of the recording, the multi-colorization,
With the expansion of applications such as full-color printing, more advanced characteristics are required for recording media. That is, the recording paper has good ink absorbency, does not cause bleeding or stains, has a high density of ink dots and is clear, and spreads ink dots in the lateral direction. Is not larger than necessary and is uniform, there is no show-through of ink, the opacity is high, the drying property of the ink is good, and buzzing or curling does not occur. It is required to have high water resistance and to prevent the ink of the recorded image from flowing out due to moisture and the like.

In response to these demands, various attempts have been made from the early stage of the development of ink jet recording paper, such as providing a coating layer (ink receiving layer) mainly composed of a pigment having good ink absorbability and an adhesive on a substrate. It was For example, a method in which a silica-based pigment is used as a pigment (JP-A-52-9074 and JP-A-55).
-51583, JP-A-56-148583, JP-A-58-72495, JP-A-58-110287), and a method of using a water-soluble polymer coating layer for the ink receiving layer (JP-A-55-55- 144172, JP-A-5
5-146786) and a method using a basic latex polymer (JP-A-57-36692).

Further, for the purpose of improving the poor water resistance inherent in the recording with the water-based ink, an attempt is made to add a water-proofing agent after ink-jet recording on the water-soluble polymer coating layer (Japanese Patent Laid-Open Publication No. Sho. 55-50396, JP-A-56-8869, etc.) and devises using specific pigments or resins that adsorb the coloring component in the aqueous ink (JP-A-55-144172, etc.). However, even these conventional inkjet recording papers have various drawbacks and cannot satisfy the ink receptivity and the recording image quality, and therefore the quality characteristics as an inkjet recording paper are satisfied in all. is not.

Further, with the recent progress of office automation, printers and plotters using the ink jet recording system have become widespread, and in particular, ink jet color recording has begun to attract attention. In this color recording, in order to reproduce the hue closer to the original image from the limited color material (ink), it is increasingly required to increase the number of colors and increase the resolution and the sharpness of the colors. Therefore, the color mixture of ink is inevitable. However, that means that the amount of ink ejected per unit area of the recording paper increases, and as a result, the occurrence of show-through due to the absorption of ink during recording, the decrease in drying property, or the occurrence of blistering. Cause a phenomenon,
The improvement has become a big issue.

[0008]

SUMMARY OF THE INVENTION The present invention relates to an ink jet recording paper, and in particular, because of excellent ink absorption at the time of recording, the show-through of the ink on the back surface of the recording paper is eliminated and the opacity is extremely high, and the ink is very high. It has excellent dryness,
Moreover, the present invention provides a high-quality inkjet recording paper having high image density and excellent quality characteristics in color developability and sharpness.

[0009]

The present invention provides an ink jet recording paper having an ink receiving layer on a base paper, wherein the base paper contains at least (a) a hydrophobic monomer having 8 to 34 carbon atoms and (b) an amino group. An ink-jet recording sheet comprising a synthetic sizing agent obtained by epoxidizing a reaction product with an amine compound having, and a water-soluble polymer compound in the ink receiving layer.

[0010]

In general, regarding the recording suitability of the ink jet recording system, when the ink absorbency of the recording paper is increased, the density of the recorded image is lowered, the sharpness of the hue and the color developability are deteriorated, and the resolution is deteriorated. Further, the ink is absorbed even near the back surface of the recording paper, and ink show-through easily occurs. On the other hand, if the ink absorbency is reduced, the image density increases, but there is a problem in that the image quality is deteriorated due to overprinting or uneven density, or the ink dries poorly and causes scratches on the recording portion. , There are contradictory issues regarding ink absorbency.

As a result of intensive studies to solve such problems, the present inventors have found that a coating solution containing a specific synthetic sizing agent in the base paper and a water-soluble polymer compound on the base paper. It has been found that an ink jet recording paper having desired excellent quality characteristics can be obtained by coating or impregnating the above with an ink receiving layer.

Since the synthetic sizing agent of the present invention can impart an appropriate sizing property to the base paper, when the coating liquid for forming the ink receiving layer is coated on the surface of the base paper, the aqueous component in the coating liquid is the base paper. It has a feature that it can be appropriately permeated to form a uniform layer, and a desired ink receiving layer having excellent ink absorbency can be effectively provided. Further, according to the examination results of the present invention, the specific sizing agent of the present invention is a direct dye in the ink,
It has been clarified that it has an excellent ability to capture a coloring component such as an acid dye. Therefore, it has a feature that the problems such as the occurrence of the show-through of the ink and the deterioration of the drying property are solved, and moreover, the excellent effects such as the effect of improving the sharpness and the coloring property of the recorded image can be exhibited. That is, it is presumed that this is because the use of the synthetic sizing agent of the present invention has an appropriate barrier property against permeation of the ink into the base paper during recording.

The synthetic sizing agent used in the present invention means a synthetic size obtained by epoxidizing a reaction product of at least (a) a hydrophobic monomer having 8 to 34 carbon atoms and (b) an amine compound having an amino group. It is an agent. As a concrete example,
For example, a copolymer of styrene and an acrylic ester reacted with polyamine, epoxidized, a copolymer of α-olefin and maleic anhydride reacted with polyamine, epoxidized, fatty acid and polyamine. There is an epoxidized product obtained by reacting with.

Among them, carbon number is 8 to 34, preferably carbon number
The higher fatty acid-based synthetic sizing agent obtained by epoxidizing the reaction product of 12 to 28 higher fatty acid and polyalkylene polyamine is particularly preferably used because the effect of the present invention is more excellent. The method for synthesizing the synthetic sizing agent is not particularly limited, and examples thereof include JP-A-50-116705 and JP-A-
It can be synthesized by the method described in JP-A-51-38600, JP-A-54-147211 and the like.

Specific examples of the higher fatty acid having 8 to 34 carbon atoms include lauric acid, myristic acid, palmitic acid,
Stearic acid, arachidic acid, behenic acid, cerotic acid, oleic acid, vaccenic acid, erucic acid, linoleic acid, linolenic acid, arachidonic acid, ricinoleic acid, cerebronic acid,
Examples include alkyl succinic acid, alkenyl succinic acid, tall oil fatty acid, and the like.

Specific examples of the polyalkylenepolyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine and dimethylpropylenediamine.

Further, specific examples of the compound to be epoxidized include epihalohydrin such as epichlorohydrin, epibromohydrin and methylepichlorohydrin.

Further, in order to constitute a synthetic sizing agent, rosin, maleated rosin, fumarized rosin, maleated petroleum resin, fumarized petroleum resin, urea, other components are included as other components.
Adipic acid, maleic acid, phthalic acid, formic acid, formalin and the like can also be used.

The synthetic sizing agent of the present invention can be used as an internally added sizing agent and / or a surface sizing agent, and is appropriately blended according to the required quality of the ink jet recording paper.
The amount contained in the base paper is adjusted, for example, in the range of 0.01 to 4% by weight, more preferably about 0.05 to 2.5% by weight, based on the absolutely dry pulp in the base paper. By the way, if the content of the synthetic sizing agent is less than 0.01% by weight, the desired effect of the present invention cannot be obtained. On the other hand, if it exceeds 4% by weight, the ink absorbability to the base paper is extremely lowered and the ink drying property is lowered. Is worse,
It is not preferable because troubles such as rubbing stains on the recording portion occur.

When a synthetic sizing agent is used as an internally added sizing agent, a rosin-based sizing agent such as a rosin emulsion, an alkyl ketene dimer-based sizing agent, an alkenyl succinic anhydride-based sizing agent, a petroleum resin-based sizing agent, or a wax-based sizing agent. Other internally added sizing agents such as sizing agents may be used in combination within the range that does not impair the effects of the present invention.

When used as a surface sizing agent, various starches, polyvinyl alcohol, carboxymethyl cellulose, latex, and styrene-acrylic or α-olefin-maleic anhydride synthetic sizes different from those of the synthetic sizing agent of the present invention are used. Agents, pigments, dyes and the like can be used together within a range that does not impair the effects of the present invention.

Regarding the method of determining the surface size,
It is not particularly limited, and for example, a two-roll or metalling blade type size press, gate roll, bill blade and short dwell coater, roll coater, air knife coater, blade coater, spraying device and the like are appropriately selected on the base paper. The method of surface size etc. is mentioned.

In addition to the above case, there is a case where the ink receiving layer is provided by sizing the surface of the base paper. However, in the present invention, the surface sizing of the base paper does not include the sizing agent in the base paper. It means to contain. That is, in the present invention, the sizing agent is included in the base paper, including the internal addition size and the surface size.

When the method of impregnating the surface of the base paper with the synthetic sizing agent of the present invention is adopted, the surface sizing agent is mixed with the above-mentioned surface sizing agent when the surface sizing is performed, and the surface sizing agent is impregnated in the paper making step. Is also possible.

The raw material of the base paper which is the base paper is not particularly limited, and is mainly wood pulp, but if necessary, non-wood pulp such as kenaf, bamboo, hemp, or polyester. Synthetic pulp such as or polyolefin, or synthetic fiber, and further inorganic fiber such as glass fiber and ceramic fiber can be used. The type and production method of pulp fibers are not particularly limited, and examples of wood pulp include chemical pulp such as softwood pulp and hardwood pulp obtained by the KP, SP, AP method, and SCP, as well as various high yields. Pulp (SGP, BSGP, BCTMP, CTMP, CGP, TMP
, RGP, CMP, etc.), or general high-quality paper including recycled pulp or recycled pulp such as DIP, medium-quality paper, etc. can be used as the base paper.

In the base paper, various papermaking fillers and papermaking internal additives can be appropriately selected and added within a range that does not impair the desired effects of the present invention. The papermaking filler is not particularly limited, for example, talc, clay, kaolin, calcined kaolin, deramikaolin, diatomaceous earth, heavy calcium carbonate, light calcium carbonate, titanium dioxide, magnesium carbonate, aluminum hydroxide,
Calcium hydroxide, magnesium hydroxide, zinc hydroxide,
Mineral fillers such as magnesium sulfate, calcium sulfate, magnesium silicate, calcium silicate, aluminum silicate, silica, aluminosilicate, bentonite and sericite, and polystyrene resin, urea resin, acrylic resin, melamine resin, benzoguanamine resin and other fine particles, and Organic synthetic fillers such as fine hollow particles can be appropriately selected and used in combination. Furthermore, pigments contained in waste paper, brokes, etc. can be effectively used as a filler.

Also, the internal additive for papermaking is not particularly limited, and various conventionally used anionic, nonionic, cationic or amphoteric retention improvers, drainage improvers and papers are used. A strength enhancer or the like is appropriately selected and used. For example, polyvalent metal compounds such as Al, Fe, Sn, and Zn (sulfuric acid band, aluminum chloride, sodium aluminate, basic aluminum chloride, basic aluminum compounds such as basic polyaluminum hydroxide) and water-dispersible alumina sol. Water-soluble aluminum compounds such as or ferrous sulfate, ferric chloride, etc.), starches such as oxidatively modified starch, pregelatinized starch, esterified starch, polyacrylamide, vegetable gum, polyvinyl alcohol, latex, polyethylene oxide, Urea resin, melamine resin, urea formaldehyde resin, melamine formaldehyde resin, polyamide polyurea formaldehyde resin, polyamide resin,
Polyamide epichlorohydrin resin, polyamide polyamine epichlorohydrin resin, epoxidized polyamide resin, polyethyleneimine resin, aldehyde starch, ketone aldehyde resin, hydrophilic crosslinked polymer particle dispersion and derivatives or modified products thereof, and various colloidal silica, bentonite, etc. A compound can be illustrated. In addition, an internal additive for papermaking such as a dye, a fluorescent whitening agent, a pH adjusting agent, a defoaming agent, a pitch control agent, and a slime control agent can be appropriately added as necessary.

When the stock is prepared, the specific conductivity (SC) of the stock is maintained at 1.5 mS / cm or less in both the preparation process and the papermaking process, and the zeta potential is 0. It is preferable to adjust to the vicinity. Further, when the surface is sized, it is possible to use a water-proofing agent, a fluorescent whitening agent, a defoaming agent, a conductive treatment agent, a pigment, a dye or the like together with the above-mentioned various surface sizing agents.

The papermaking method is not particularly limited. For example, an acidic papermaking method having a papermaking pH of about 4.5, or an alkaline filler such as calcium carbonate as a main component, and a papermaking pH of about 6 to a weak acidity to about. It can be applied to all papermaking methods such as the so-called neutral papermaking method, which has a weak alkalinity of 9, and the paper machine can be a Fourdrinier paper machine, a twin wire paper machine,
A circular net paper machine, a Yankee paper machine, or the like can be used as appropriate.

Next, a method for preparing a coating liquid containing the water-soluble polymer compound of the present invention for forming an ink receiving layer on a base paper will be described. Examples of the water-soluble polymer compound in the present invention include starches such as oxidatively modified starch, enzyme modified starch, thermochemically modified starch, cationic starch, amphoteric starch, esterified starch, and cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, Natural or semi-synthetic polymers such as casein, gelatin and soy protein. Alternatively, polyvinyl alcohols such as completely or partially saponified polyvinyl alcohol, acetoacetylated polyvinyl alcohol, carboxy-modified polyvinyl alcohol, olefin-modified polyvinyl alcohol, and silyl-modified polyvinyl alcohol are listed, and at least one of these is highly water-soluble. It is important to appropriately select and use the molecular compound.

The content of the water-soluble polymer compound is preferably in the range of 10 to 99% by weight, preferably 15 to 95% by weight, based on the total solid content in the coating liquid. By the way, if the blending amount is less than 10% by weight, the strength of the surface of the ink receiving layer becomes weak and paper dust is likely to be generated. It is not preferable because it causes clogging and adversely affects the image quality. On the other hand, in the case of a coating liquid consisting essentially of a water-soluble polymer such as 99% by weight, the desired effect of the present invention cannot be obtained, which is not preferable.

Further, in the coating liquid for forming the ink receiving layer, various aqueous polymer compounds are used in combination depending on the purpose. These are, for example, melamine resin, urea resin, epichlorohydrin resin, epoxy resin, alkyd resin,
Polyurethane resin, polyethyleneimine resin, polyamide resin, polyethyleneimine resin, polyvinylpyrrolidone resin, polyvinyl butyral resin, poly (meth) acrylic acid or its copolymer, (meth) acrylic acid ester resin, acrylamide -Based resin, maleic anhydride copolymer, polyester-based resin, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer latex, acrylic polymer latex such as acrylate ester copolymer, ethylene-vinyl acetate copolymer Vinyl-based polymer latexes such as coalesces, functional group-containing modified polymer latexes obtained by adding anionic groups and / or cationic groups to these various polymer latexes, and further, cationic resins as dye fixing agents, etc. Is mentioned.

The coating liquid is prepared by containing a water-soluble polymer compound, but if an optional pigment is added, an ink jet recording paper can be obtained in which a clearer recorded image can be obtained.

The pigment is not particularly limited, and examples thereof include kaolin, derami kaolin, aluminum hydroxide, satin white, heavy calcium carbonate, light calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, calcined kaolin, and talc. , Silica, finely divided silica, zinc oxide, zinc carbonate, zinc sulfide, alumina, finely divided alumina, diatomaceous earth, white carbon, aluminum silicate, calcium silicate, magnesium silicate, magnesium aluminate silicate, magnesium oxide, magnesium carbonate, aluminosilicate, Mineral pigments such as colloidal silica, activated clay, bentonite, zeolite, sericite, lithopone, porous pigments, polystyrene resins, urea resins,
Acrylic resin, melamine resin, benzoguanamine resin,
In addition, one or more kinds of known pigments such as fine particles such as organic pigments, porous fine particles, and hollow particles are appropriately used depending on the quality target of the inkjet recording paper.

Among these, the porous pigment and the porous fine particles effectively contribute to the transfer of the aqueous ink medium to the base paper and the retention of the coloring component, and are effective in exhibiting excellent ink receptivity. Therefore, it can be preferably used. Such a porous pigment and porous fine particles are not particularly limited in kind, production method, etc., and have a specific surface area by the BET specific surface area method of 150 m ² / g or more, more preferably 200 m ² / g or more, and Average particle size of dispersed particles in a coating liquid for forming an ink receiving layer (Coulter counter, A
Those having a P value of 50 μm) of 0.5 to 15 μm, more preferably 1 to 10 μm can be preferably used. Incidentally, if the specific surface area is less than 150 m ² / g, the ink receptivity will be insufficient, causing bleeding and stains. The average particle size is 0.5μ
If it is less than m, the sharpness of the recorded image is lost to give a dull image, while if it exceeds 15 μm, the lateral spread of the ink dots is uneven and a recorded image with excellent resolution cannot be obtained.

The pigment content is 10 to 90% by weight of the total solid content.
It is preferable that the compounding amount be in the range of in order to obtain the desired effects of the present invention. When a pigment is included, it is desirable to use a powder having a whiteness of 75% or more, preferably 80% or more, because the whiteness of the recording paper can be improved.

If necessary, in addition to these, a thickener, a release agent, a penetrant, a wetting agent, a heat gelling agent, a sizing agent, a defoaming agent, a foam suppressor, and a foaming agent may be added to the coating liquid. Agents, colorants, optical brighteners, UV inhibitors, antioxidants, quenchers, preservatives, antistatic agents, crosslinking agents, dispersants, lubricants, plasticizers, pH
It is also possible to appropriately mix various auxiliaries such as a regulator, a fluidity improver, a solidification accelerator, and a water resistant agent. If the above-mentioned coating liquids containing various components are not uniformly dispersed due to aggregation or the like, prepare two or more separate coating liquids and
It is also possible to obtain the target ink receiving layer by performing smearing more than once.

The coating liquid thus prepared is coated or impregnated on the base paper, but the coating or impregnating amount need not be unnecessarily increased as long as the ink jet recording suitability such as ink receptivity is satisfied. Generally, dry weight of 0.5-
30 g / m ^2, is preferably coated in the range of from 1 to 20 g / m ^2.

As the coating or impregnating device, for example, blade coater, air knife coater, roll coater, reverse roll coater, bar coater, curtain coater, die slot coater, gravure coater, champlex coater, brush coater, two roll or metering blade. Formula size press, gate roll, bill blade,
An ordinary coating device such as a short dwell coater or an ordinary impregnation device such as a pre-wetting method, a float method, a squeeze roll method, a doctor bar method or the like can be appropriately used. Of course, these devices may be on-machine or off-machine coaters.

The coated or impregnated ink jet recording paper is smoothed in a usual drying process or surface treatment process and has a water content of 3 to 10% by weight, preferably 4 to 8% by weight.
It is finished to the extent of paper. In addition, when smoothing the base paper, the smoothing treatment is carried out in a normal surface treatment step without any particular effort, but further, it may be heated and / or non-heated with a metal roll. It is also possible to finish the sheet by passing it through a pressure nip composed of a heated elastic roll.

If necessary, the front surface and / or the back surface of the recording paper may be subjected to surface treatment such as antistatic treatment and writing aptitude (printing aptitude) imparting treatment, and ultraviolet rays may be applied to arbitrary positions on the recording paper. It is also possible to add auxiliaries such as an antioxidant and an antioxidant to improve the storability of a recorded image.

[0042]

The present invention will be described in more detail with reference to the following examples, but the scope of the invention is not limited thereto.
Unless otherwise specified, "part" and "%" in the examples mean "part by weight" and "% by weight", respectively.

[Sizing Agent] Table 1 shows the types and compositions of the sizing agents added to the paper stock or used for the surface size.
As shown in. Among these sizes,
A, B, C, D, E are specific synthetic sizes of the present invention.

Example 1 [Preparation of base paper] NBKP (freeness = csf: 520 ml) 10 parts, LB
A pulp slurry containing 90 parts of KP (freeness = csf: 480 ml) is mixed with light calcium carbonate as a filler (trade name: TP
-121S / Okutama Industry Co., Ltd.) 12 parts, sulfuric acid band 0.5
Part, cationic starch (trade name: Amilofax T-22
00 / Matsutani Chemical Co., Ltd.) and 0.5 part of the sizing agent A shown in Table 1, and the pulp slurry was diluted with white water, and then colloidal silica (BMA / Nissan Eka Nobel) was added. Addition of 0.1 parts pH 7.9, concentration 1.0
% Stock was prepared. After making paper from this stock using a twin-wire paper machine and drying, the surface size was adjusted to a solid content of oxidized starch of 1.5 g / m ² with a gate roll coater, and the weight of the rice was 75 g / m ^2. I got the base paper.

[Preparation of coating liquid] 100 parts (solid content; the same applies hereinafter) of a porous pigment (trade name: Mizuka Seal P-78D / manufactured by Mizusawa Chemical Co., Ltd.) (trade name: Sumirez Resin # 1001 / manufactured by Sumitomo Chemical Co., Ltd.) ) 5 parts (solid content ratio with respect to the pigment; the same applies hereinafter) was dispersed and mixed using a Choles disperser. Next, polyvinyl alcohol (trade name: PVA-110 / manufactured by Kuraray Co., Ltd.)
Add 25 parts, and further mix fluorescent dye, antifoam and water,
A coating liquid for forming the ink receiving layer was prepared by stirring and mixing.

[Formation of Ink Receiving Layer] This coating solution was applied onto the base paper obtained as described above at a dry coating amount of 9.0 g / m ^2.
Coating and drying with a rod blade coater to achieve
² inkjet recording sheets were obtained.

Examples 2 to 5 In Example 1, the addition of sizing agent A was stopped, 0.3 parts of sizing agent B (Example 2), 0.5 parts of sizing agent C (Example 3), and sizing agent D were added. InkJet recording paper having a basis weight of 84 g / m ^{2 in} the same manner as in Example 1 except that 0.5 parts (Example 4) and 2 parts (Example 5) of sizing agent E were added to prepare the base paper. Got

Example 6 [Preparation of base paper] In Example 1, the pulp formulation was changed to 10 parts of NBKP, 40 parts of LBKP, and 50 parts of recycled pulp from OA waste paper, and the internal chemicals were also changed. Then, 12 parts of talc as a filler, 0.3 part of sizing agent A, 0.2 parts of sizing agent I (rosin sizing agent) and 2 parts of sulfuric acid band were added, and after the pulp slurry was diluted with white water, pH 5.1, concentration
A 1.1% stock was prepared. After making a paper from this stock using a Fourdrinier paper machine and drying, the surface size was adjusted to a solid content of 2.5 g / m ² of oxidized starch with a gate roll coater, and the weight of the rice was 75 g / m ^2. An ink jet recording paper having a basis weight of 84 g / m ² was obtained in the same manner as in Example 1 except that the above base paper was obtained.

Example 7 In Example 6, the addition of the sizing agent A to the stock was stopped,
Sizing agent I: 0.2 parts only, and further using an oxidized starch and a sizing agent B together in a size press, the surface size was adjusted so that the coating amount of the sizing agent B was 0.1 g / m ^{2 in} solid content, and base paper except that was prepared in the same manner as in example 6 a basis weight in the 84 g / m ²
The inkjet recording paper of was obtained.

Example 8 [Preparation of base paper] In Example 1, the mixed filler of talc and light calcium carbonate (trade name: Callite KT / manufactured by Shiraishi Industry Co., Ltd.) (mixing ratio 3: 1) was changed to 16 parts. Was prepared in the same manner as in Example 1 except that the weight of the rice was 78 g / m 2.
A base paper of ² was obtained.

[Preparation of coating liquid] In Example 1, a porous pigment (trade name: Mizuka Seal P-78D / manufactured by Mizusawa Chemical Co., Ltd.)
100 parts (solid content; hereinafter the same) were dispersed and mixed in 20 parts (trade name: Sumirez Resin # 1001 / Sumitomo Chemical Co., Ltd.) (solid content ratio to pigment; the same hereinafter) using a Choles disperser. .. Next, polyvinyl alcohol (trade name: PVA
-107 / made by Kuraray Co., Ltd.) 400 parts were added, and further, a fluorescent dye, an antifoaming agent and water were mixed, stirred and mixed to prepare a coating liquid for forming an ink receiving layer.

[Formation of Ink Receiving Layer] This coating solution was applied onto the base paper obtained as described above at a dry coating weight of 6.0 g / m ^2.
An ink jet recording paper having a basis weight of 84 g / m ² was obtained in the same manner as in Example 1 except that the coating was carried out using an air knife coater.

Comparative Example 1 In the same manner as in Example 1 except that the base paper was prepared without adding the sizing agent A, the basis weight of the rice was 84 g / m ^2.
The inkjet recording paper of was obtained.

Comparative Example 2 In the same manner as in Example 1 except that 5 parts of the sizing agent A was added to prepare the base paper, the weight of the rice was 84 g / m2.
An inkjet recording paper of m ² was obtained.

Comparative Examples 3 to 5 In Example 1, the addition of the sizing agent A was stopped and 1.5 parts of the sizing agent F (Comparative Example 3), 0.7 parts of the sizing agent G (Comparative Example 4) and H of the sizing agent H were added. An inkjet recording paper having a basis weight of 84 g / m ² was obtained in the same manner as in Example 1 except that the base paper was prepared by changing the addition to 1.2 parts (Comparative Example 5).

Comparative Example 6 In Example 7, substituting the sizing agent A used for the surface size with the sizing agent J, the coating amount of the sizing agent J was solid content.
An ink jet recording paper having a basis weight of 84 g / m ² was obtained in the same manner as in Example 7 except that the base paper was prepared with the surface size adjusted to 0.1 g / m ² .

Comparative Example 7 The procedure of Example 8 was repeated except that the addition of the sizing agent A was stopped and the sizing agent G was changed to 0.7 part to prepare a base paper. An inkjet recording paper of / m ² was obtained.

The above 15 kinds of ink jet recording papers thus obtained were measured and quality evaluated by the following methods, and the obtained results are shown in Table 2.

[Measurement of Chromaticity (Coloring Property) of Coloring Part of Recorded Image] Recording Device (Image Jet Printer IO-735
A predetermined pattern was recorded using a mold (manufactured by Sharp Corporation), and the chromaticity (a *, b *) of the red-colored portion and the green-colored portion of the recording portion was measured using EL REFO 2000 (manufactured by Data Color Corporation). As for the relationship between chromaticity (a *, b *) and hue, the value of chromaticity a * is positive as described in Paper Pulp Technology Times Vol 22, No 11 (November 1979 issue), pages 58 to 61. The larger the value toward the side, the better the red color develops (the greater the degree of red), and the larger the value of the chromaticity a * becomes toward the negative side, the better the color develops the green (the degree of green increases). Means that.

[Evaluation of sharpness (saturation) of recorded image] Saturation (C *) was calculated by the following formula based on the above measured chromaticity,
The sharpness of the red-colored portion and the green-colored portion of the recorded area was evaluated. C * = {(a *) ² + (b *) ² } ^1/2 Here, the larger the saturation value of C *, the better the sharpness.

[Evaluation of ink show-through] After the above recording, the degree of ink bleeding on the back surface of the recording paper was visually evaluated according to the following evaluation criteria. A: Excellent without ink show-through. ◯: There is almost no ink show-through, which is good. Δ: The show-through of the ink is recognized and is slightly inferior. X: There is show-through of ink, which is a problem in practical use.

[Evaluation of Ink Dryness] Regarding the above-mentioned recording portion, the recording portion immediately after recording was rubbed with gauze, and the degree of stain due to ink spread was visually evaluated according to the following evaluation criteria. ⊚: Excellent in dryness without stains. ◯: Almost no stain and good drying property. Δ: Staining is slightly recognized, and the drying property is slightly inferior. X: A lot of stains and poor drying property.

[0063]

[Table 1]

[0064]

[Table 2]

[0065]

As is clear from the results of the examples of Table 2, the ink jet recording paper obtained by the method of the present invention has no show-through of ink on the back surface of the recording paper and good ink drying property. Moreover, the ink jet recording paper has a high image quality and has excellent quality characteristics in color development and sharpness of the recording portion.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fudou Yasuda 4-3-1 Jōkoji, Amagasaki City, Hyogo Prefecture Kanzaki Paper Co., Ltd. Kanzaki Mill

Claims (4)

[Claims] 1. An ink jet recording paper having an ink receiving layer provided on a base paper, the reaction formation of at least (a) a hydrophobic monomer having 8 to 34 carbon atoms and (b) an amine compound having an amino group in the base paper. An ink-jet recording sheet comprising a synthetic sizing agent obtained by epoxidizing a material and a water-soluble polymer compound in the ink receiving layer. 2. The synthetic sizing agent is a higher fatty acid-based synthetic sizing agent obtained by epoxidizing a reaction product of at least (a) a higher fatty acid having 8 to 34 carbon atoms and (b) a polyalkylene polyamine. 1. The inkjet recording paper according to 1. 3. The ink jet recording paper according to claim 1, wherein the base paper contains a synthetic sizing agent in an amount of 0.01 to 4.0% by weight based on the absolutely dry pulp. 4. The ink jet recording paper according to claim 1, further comprising a pigment in the ink receiving layer.