JP2011148194A - Inkjet recording paper - Google Patents

Abstract

An object of the present invention is to provide an ink jet recording paper of a type in which an ink fixing agent is supplied to the recording paper before, after, or both before and after printing, and an appearance similar to coated paper for offset printing and excellent ink jet aptitude. It is to provide an ink jet recording paper excellent in strength of a coating layer in a printing part immediately after printing.
In an inkjet recording paper provided with a coating layer mainly containing a pigment and an adhesive on at least one side of a support, calcium carbonate is used as a pigment of the coating layer, and the total pigment solid content of the coating layer is 100 mass. 60 parts by mass or more with respect to parts, 3 to 10 parts by mass of synthetic rubber latex as an adhesive, and 3 to 10 parts by mass in total of either modified starch or polyvinyl alcohol alone or both. Inkjet recording paper.
[Selection figure] None

Description

  The present invention relates to an inkjet recording paper used in a printing machine that performs high-speed and continuous printing by an inkjet method, and particularly to a printing machine that includes a step of supplying an ink fixing agent to a recording paper before, after, or both before and after printing. The present invention relates to a suitable inkjet recording paper. More specifically, the present invention relates to an ink jet recording paper that provides both an appearance like coated paper for offset printing and excellent printability of an ink jet system, and in particular, has excellent coating layer strength in a printed portion after printing.

  Applications for printing using the inkjet method are not limited to terminal PC printers, fax machines, or copiers, but are also being put into practical use in the so-called on-demand printing field that enables various types of small lot printing, variable information printing, etc. The technological progress is remarkable. In recent years, with the improvement in printing speed and image quality, the use of the number of printed copies has been studied even in an area where conventional offset printing or gravure printing has been performed.

  The ink jet method is a method in which fine ink droplets are ejected onto the surface of a recording paper to form an image. Recent technological advances are remarkable, the image quality is extremely high, and the weather resistance, which was a weak point, has been greatly improved by the appearance of pigment inks. However, the inkjet method has a problem that a relatively long drying time is required.

  As a technology that is expected to be put to practical use in the future and whose application is expected to be widespread, cationic ink fixing is performed in advance or after ink landing on the portion of the recording paper on which the anionic ink containing the coloring material is to land. There is a method of printing by supplying an agent (for example, see Patent Documents 1 to 4), and pigment ink is considered to be the mainstream as the ink type. In addition, in order to cope with high speed and high image quality, it is considered that a printer having an ink drying function becomes the mainstream particularly in the field of mass printing. As recording paper, diversion of existing offset printing paper, electrophotographic paper, and inkjet paper can be considered. However, with conventional recording paper, the coating layer strength of the printing section to which the ink fixing agent and ink are supplied is not sufficient, and the printing section is particularly damaged by rubbing during high-speed printing, folding or cutting in processing performed after printing, etc. There is a problem that the coating layer is destroyed, and improvement is demanded.

  The ink fixing agent and ink supplied from the printing machine to the recording paper use water and a water-soluble organic solvent as a medium, mainly for the purpose of preventing drying with a supply device or an ink nozzle. The ratio varies depending on the characteristics of the printing press, but water: organic solvent = 5: 5 to 9: 1 is common. In the ink fixing agent or ink, the coloring material is dispersed or dissolved in this medium (hereinafter referred to as “ink solvent”), and in addition, a surfactant or an adhesive is generally blended. The organic solvent selected for the ink solvent is an organic substance having an affinity for water, such as alcohols and ethers, and has various structures. The coating layer of inkjet recording paper is not only easy to absorb such ink solvent, but also needs to maintain sufficient coating layer strength while the ink is absorbed, retained, dried and used as printed matter. .

Japanese Patent Laid-Open No. 10-016376 Japanese Patent No. 397794 JP 2002-029141 A JP 2003-048317 A

  Ink used in a printing machine that performs high-speed and continuous printing by an inkjet method contains water and a water-soluble organic solvent as an ink solvent. The present inventor reduces the interaction and bonding between adhesives contained in the coating layer by absorbing the ink solvent mixed with water and the organic solvent into the coating layer, and the ink solvent is dried. It was also found that the adhesive interaction does not recover, and as a result, the coating layer strength decreases, that is, the ink solvent resistance decreases.

  An object of the present invention is an ink jet recording paper used in a printer that performs high-speed and continuous printing by an ink jet method, and particularly includes a step of supplying an ink fixing agent to the recording paper before, after, or both before and after printing. The present invention relates to an inkjet recording paper suitable for a printing machine. More specifically, it provides both an appearance like coated paper for offset printing and excellent printability by an ink jet method, and in particular without reducing the interaction and bonding between adhesives contained in the coating layer due to the ink solvent. An object of the present invention is to provide an ink jet recording paper having excellent ink solvent resistance and excellent coating layer strength of a printed portion after printing.

  As a result of intensive studies to solve the above problems, the present inventors have invented the following ink jet recording paper. That is, in an inkjet recording paper in which a coating layer mainly containing a pigment and an adhesive is provided on at least one side of a support, calcium carbonate is used as a pigment for the coating layer, and 100 parts by mass of the total pigment solid content of the coating layer Inkjet, characterized in that it contains 60 parts by mass or more, 3-10 parts by mass of synthetic rubber latex as an adhesive, and 3-10 parts by mass of either modified starch or polyvinyl alcohol alone or in total. Recording paper.

  Preferably, the synthetic rubber latex is a styrene-butadiene-based latex, contains 5 to 50% acrylonitrile as a monomer component of rubber, and has a gel content of 70% or more.

  Preferably, the modified starch is corn starch obtained by phosphoric acid esterification or hydroxyethyl etherification, and after cooking, the solid content concentration is 30% by mass and the B-type viscosity at 60 ° C. is 200 mPa · s or less.

  Preferably, the polyvinyl alcohol has a saponification degree of 97% or more and a polymerization degree of 300 to 1500.

  According to the present invention, an ink jet which shows an appearance like coated paper for offset printing and is excellent for an ink jet printing machine having means for supplying an ink fixing agent to a recording paper before, after, or before and after printing. It is possible to provide an ink jet recording paper that exhibits the printing suitability of the system, has particularly excellent ink solvent resistance, and has a property of being excellent in the coating layer strength of the printed portion after printing.

  Hereinafter, the ink jet recording paper of the present invention will be described in detail. Inkjet recording paper is provided with a coating layer on at least one side of a support.

<Coating layer>
In the present invention, the coating layer contains 60 parts by mass or more of calcium carbonate as a pigment with respect to 100 parts by mass of the total pigment solid content of the coating layer, 3-10 parts by mass of synthetic rubber latex as an adhesive, and modified starch 3 to 10 parts by mass of any one of polyvinyl alcohol and a total of both. Preferably, the synthetic rubber latex contains 4 to 8 parts by mass, or the modified starch and / or polyvinyl alcohol is 4 to 8 parts by mass.

  The total amount of the synthetic rubber latex and the total adhesive including the modified starch and / or polyvinyl alcohol is preferably 6 to 20 parts by mass, more preferably 8 to 16 parts per 100 parts by mass of the total pigment solid content. Part by mass.

  In the present invention, the coating layer contains modified starch and / or polyvinyl alcohol in addition to calcium carbonate and synthetic rubber latex, thereby exhibiting excellent coating layer strength in the printed portion. In this invention, content contained in the coating layer of a calcium carbonate is 60 mass parts or more with respect to 100 mass parts of total pigment solid content of a coating layer, Preferably it is 70 mass parts or more.

  Calcium carbonate used for the coating layer in the present invention is a so-called heavy carbonate produced by industrially refining and processing naturally produced limestone ore through processes such as washing, grinding and classification. Calcium is preferred. Moreover, if the calcium carbonate component is sufficiently contained, calcium carbonate obtained from raw materials other than natural limestone through the same steps as heavy calcium carbonate can be used. Examples of such raw materials include light calcium carbonate synthesized from calcium hydroxide, biological minerals, waste from cities and industries, and the like. As a method for controlling the average particle diameter, a wet pulverization method using a wet medium stirring pulverizer is most suitable. Examples of wet pulverizers include Imex, Ashizawa Finetech, Mitsui Mining, Hosokawa Micron, etc. There are vertical and horizontal types. On the other hand, there is a dry pulverization method, but the dry pulverization method is suitable for use as coarse pulverization before the wet pulverization. A mill etc. are mentioned.

  Calcium carbonate can adjust the average particle size by controlling the pulverization time and slurry flow rate of wet pulverization, preferably the volume average particle size determined from the volume-based particle size distribution is 0.3 to 3.0 μm, Preferably it is 0.5-2.5 micrometers. If the volume average particle size is larger than 3.0 μm, the surface smoothness and ink absorbability of the ink jet recording paper may be inferior. If it is smaller than 0.3 μm, the viscosity of the calcium carbonate slurry increases, It may be inferior in operability.

  Measurement of the particle size of calcium carbonate uses a particle size distribution measuring apparatus of a laser diffraction / scattering method. A typical example is an apparatus manufactured by Microtrac. Inc. The volume average particle size of calcium carbonate is a value calculated from a volume-based particle size distribution obtained by a particle size distribution measuring apparatus using a laser diffraction / scattering method.

  In the present invention, as other pigments used in the coating layer on the support, in addition to calcium carbonate in the present invention, kaolin, synthetic silica, colloidal silica, talc, satin white, lithopone, titanium dioxide, alumina, aluminum hydroxide Zinc oxide, magnesium carbonate, organic pigments, those obtained by cationic modification thereof, or a composite of two or more of these. The content of the pigment other than calcium carbonate is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, with respect to 100 parts by mass of the total pigment solid content of the coating layer in order not to impair the characteristics.

  In this invention, a coating layer contains 3-10 mass parts of synthetic rubber latex as an adhesive agent with respect to 100 mass parts of total pigment solid content, and 3-10 mass parts of modified starch and / or polyvinyl alcohol. By combining the water resistance of the synthetic rubber latex and the organic solvent resistance of the modified starch and / or polyvinyl alcohol, the ink solvent resistance of the adhesive of the coating layer can be obtained. When the content of the synthetic rubber latex, modified starch and / or polyvinyl alcohol is not within the above range, the ink solvent resistance of the adhesive cannot be obtained, and the coating layer strength decreases.

  The synthetic rubber latex used in the coating layer in the present invention is a dispersion of synthetic rubber obtained by addition polymerization or copolymerization such as polybutadiene, nitrile, and chloroprene. Furthermore, the main component is an aliphatic conjugated diene compound typified by butadiene, an aromatic vinyl compound typified by styrene, a vinyl unsaturated carboxylic acid ester compound, a vinyl unsaturated carboxylic acid, a vinyl compound having a cyano group, It is a dispersion obtained by copolymerizing other vinyl compounds. Of these, styrene-butadiene latex is preferred.

  The styrene-butadiene latex used for the coating layer in the present invention preferably contains 5 to 50% acrylonitrile as a monomer component of the synthetic rubber and has a gel content of 70% or more. More preferably, the monomer component of acrylonitrile satisfies 10 to 40% in terms of moles, the gel content is 80% or more, or both. The ink solvent resistance of the synthetic rubber latex can be improved by having an acrylonitrile component of 5 to 50% in terms of moles and by making the gel content 70% or more. Result With such a styrene-butadiene latex, the coating layer strength of the printed part after printing can be further improved. However, when the acrylonitrile component exceeds 50%, the coating layer strength may not be further improved.

  In the present invention, the gel content is determined by immersing the synthetic rubber latex dried in an organic solvent such as toluene or benzene and sufficiently dissolving it, removing the organic solvent and removing the undissolved residue, and drying the synthetic compound before immersion. This is a value determined from the ratio of the mass of the residue to the mass of the rubber latex.

  The modified starch used in the coating layer in the present invention is a hydroxyethylated starch, oxidized starch, etherified starch, phosphate esterified starch, enzyme-modified starch, or a modified starch obtained by processing starch purified from a natural plant. Cold water soluble starch obtained by drying.

  The modified starch used for the coating layer in the present invention is preferably corn starch that has been phosphorylated or hydroxyethyl etherized, and after cooking, the solid content concentration is 30% by mass, and the B-type viscosity at 60 ° C. is 200 mPa · It is preferable that it is s or less. More preferably, the B-type viscosity is 60 mPa · s or less. Such a modified starch can further improve the coating layer strength of the printed portion after printing. Cooking is a treatment in which the granular modified starch is dispersed in water and then heated and stirred for 30 minutes to 1 hour while maintaining a temperature of 90 ° C. or higher, preferably 95 ° C. or higher.

  The modified starch is a corn starch that has been phosphorylated or hydroxyethyl etherized and, after cooking, has a solid content concentration of 30% by mass and a B-type viscosity at 60 ° C. of 200 mPa · s or less while acting as an adhesive. High hydrophilicity and low viscosity, excellent miscibility with synthetic rubber latex in the coating liquid state, ink solvent resistance is improved by forming an admixture with water-resistant synthetic rubber latex, and excellent coating It is thought that layer strength is obtained.

  The polyvinyl alcohol used in the coating layer in the present invention is a polymer produced by a process called saponification, in which polyvinyl acetate is hydrolyzed with sodium hydroxide, and is acetoacetylated, carboxylated, sulfonated. Also included are modified or functionalized polyvinyl alcohols such as cationization.

  In the present invention, the polyvinyl alcohol used for the coating layer preferably has a saponification degree of 97% or more and a polymerization degree of 300 to 1500. More preferably, the saponification degree is 98% or more, the polymerization degree is 400 to 1200, or both. Such polyvinyl alcohol can further improve the coating layer strength of the printed portion after printing.

  The polyvinyl alcohol used for the coating layer in the present invention has a saponification degree of 97% or more and a polymerization degree of 300 to 1500, so that it acts as an adhesive and has high hydrophilicity and low viscosity, and a synthetic rubber in a coating liquid state. It is considered that ink solvent resistance is improved by forming an admixture with a water-resistant synthetic rubber latex that is excellent in miscibility with latex, and more coating layer strength can be obtained.

  In the present invention, the coating layer can use other adhesives other than synthetic rubber latex, modified starch, and polyvinyl alcohol to the extent that the effects of the present invention are not impaired. Other adhesives that can be used include acrylic resins, various copolymer latexes such as polyvinyl acetate and ethylene-vinyl acetate, sodium polyacrylate, polyethylene oxide, polyacrylamide, urea, melamine and other formalin resins, polyethylene Examples thereof include water-soluble synthetic resins such as imine, polyamide polyamine, and epichlorohydrin polycondensate. Furthermore, natural polysaccharides such as dextrin, mannan, chitosan, arabinogalactan, glycogen, inulin, pectin, hyaluronic acid, carboxymethylcellulose, hydroxyethylcellulose, oligomers thereof, and modified products thereof can be mentioned. Examples thereof include natural proteins such as casein, gelatin, soybean protein, and collagen, and modified products thereof, and synthetic polymers and oligomers such as polylactic acid and peptides. These can be used alone or in combination. Further, these adhesives can be used after cation modification.

  In the coating layer of the present invention, various auxiliary agents such as a thickener, a dispersant, an antifoaming agent, a surfactant, a pH adjuster, a water resistant agent, a colorant and the like are used as necessary. Can be contained.

In the present invention, the method for coating the coating layer is not particularly limited, and various film transfers such as a size press having a puddle, a metering size press, a gate roll, and a shim sizer, a rod, a blade coater, and an air knife coater. Each method such as curtain coater, spray coater, and cast is appropriately used. A coating layer is 3-30 g / m < ² > per side, Preferably it is 5-25 g / m < ² >.

<Intermediate layer>
The ink jet recording paper of the present invention has an intermediate layer mainly containing a pigment and an adhesive between the support and the coating layer to improve the smoothness of the recording paper or to improve the coating property. It may be provided intentionally. The intermediate layer is preferably selected from the materials and coating methods mentioned in the previous section for the coating layer, and preferably has a solid content of ² to 30 g / m ² per side.

<Support>
In the present invention, the support is preferably paper made of wood pulp fibers in sheet form. Others include plant fibers such as cotton, hemp, bamboo, sugarcane, corn, and kenaf, animal fibers such as wool and silk, cellulose regenerated fibers such as rayon, cupra, and lyocell, semi-synthetic fibers such as acetate, polyamide fibers, and polyester fibers. Use fiber, polyacrylonitrile fiber, polyvinyl alcohol fiber, polypropylene fiber, polyvinylidene chloride fiber, polyurethane fiber, etc., fiber, inorganic fiber such as glass fiber, metal fiber, carbon fiber, etc. You can also

  These fibers include heavy calcium carbonate, light calcium carbonate, kaolin, talc, clay, titanium dioxide, aluminum hydroxide, silica, alumina, organic pigments, various fillers, adhesives, sizing agents, fixing agents, Various compounding agents such as a yield agent and a paper strength enhancer can be suitably contained in accordance with each step and each material.

  A general paper making process is used as a manufacturing method for forming each fiber into a sheet. Others used in the non-woven fabric and filter fields, such as wet method, dry method, chemical bond, thermal bond, spun bond, spun lace, water jet, melt blow, needle punch, stitch blow, flash spinning, tow opening, etc. A process can also be used.

  The support is preferably subjected to a surface size press in order to obtain the required size, surface strength, and air permeability. As components of the surface size press solution, starch purified from natural plants, hydroxyethylated starch, oxidized starch, etherified starch, phosphate esterified starch, enzyme-modified starch and cold water soluble starch obtained by flash drying them, Examples include acrylic surface sizing agents such as acrylic, styrene-acrylic, styrene-maleic acid, styrene-olefin, acrylic-vinyl acetate, and olefinic surface sizing agents such as olefin-maleic acid and diisobutylene-maleic acid. In addition, all materials used for the coating layer can be used as appropriate.

  Moreover, in this invention, cationic polymers, oligomers, and polyvalent cation salts, such as an inkjet ink water-resistant agent, an inkjet ink fixing agent, and an inkjet printing suitability improver, can be contained as a component of the surface size press liquid. Cationic polymers and cationic oligomers are typically amines with which protons are easily coordinated, and copolymers of monomers containing primary, secondary or tertiary amino groups, or quaternary ammonium salts and other monomers. Is mentioned. Examples of the polyvalent cation include divalent cations such as magnesium, calcium, strontium, barium, nickel, zinc, copper, iron, cobalt, tin and manganese, trivalent cations such as aluminum, iron and chromium, titanium, Examples include zirconium tetravalent cations and complex ions thereof.

Examples of the method for applying the surface size press liquid include various film transfers such as a size press having a liquid pool, a metal ring size press, a gate roll, and a shim sizer. Cationic polymers, cationic oligomer, the coating amount of polyvalent cations is 0.1 to 5.0 g / ^{m 2} as a solid per side content, more preferably from 0.5 to 3.0 g / ^{m 2.}

<Calendar processing>
Support, support provided with an intermediate layer, support provided with an intermediate layer and a coating layer, support provided with a coating layer, the required density, smoothness, air permeability, water absorption, appearance, Calendar processing can be applied to obtain glossiness. A device composed of a combination of hard rolls, elastic rolls, a pair of hard rolls and elastic rolls is preferably used as a machine, and is called a machine calendar, soft nip calender, super calender, multi-stage calender, multi-nip calender, etc. In some cases, it may be intentionally heated. The temperature of the roll at the time of heating may reach a high temperature of about 250 ° C. from a medium low temperature of about 40 ° C. Also, an apparatus composed of a combination of a belt and a roll can be used, which is called a shoe calender, a metal belt calender, or the like. The microscopic shape of the roll surface is not particularly limited, and it is possible to use a smoothed or concavo-convex processed surface within a range that does not impair the present invention, such as mirror surface, matte, and embossing.

The ink-jet recording paper finally obtained is processed into a large or small sheet or roll according to the intended use to obtain a product. During storage, it is preferable to apply moisture-proof packaging to avoid moisture absorption. The basis weight of the product is not particularly limited, but is about 40 to 300 g / m ² .

  Examples of the present invention will be described below, but the present invention is not limited to these examples. Further, “parts” and “%” shown in the examples indicate parts by mass and mass% unless otherwise specified.

(Example 1) to (Example 48) and (Comparative Example 1) to (Comparative Example 20)
An ink jet recording paper was prepared according to the following contents.

<Preparation of surface size press solution>
Oxidized corn starch was dispersed in water and then heated and stirred for 30 minutes while maintaining the temperature at 95 ° C. or higher. Water was added to finally make the solid concentration of the liquid about 5% by mass.

<Preparation of pulp slurry>
LBKP (Drainage 420 mlcsf) 80 parts NBKP (Drainage 450 mlcsf) 20 parts Light calcium carbonate filler (expressed in ash content in base paper) 11 parts Cationized starch 0.50 parts Cationic polyacrylamide yield improver 0.01 parts Alkyl Ketene dimer internal sizing agent 0.05 parts Sulfuric acid band 1 part <Preparation of support>
A pulp slurry was prepared with the above-described pulp and internal chemicals in the above composition, and a base paper was made with a long net paper machine at a basis weight of 70.0 g / m ² . Incidentally, components of the surface size press solution is double-sided 2.0 g / ^{m 2} coated on solids, contained in the basis weight of 70.0 g / ^{m 2} of support.

<Preparation of coating solution>
Pigment blending number is listed in Tables 1, 2 and 3. Synthetic rubber latex blending number is listed in Tables 1, 2 and 3. Polyvinyl alcohol blending number is listed in Tables 1, 2 and 3. Modified starch blending parts are listed in Tables 1, 2 and 3. Calcium stearate lubricant 0.30 part Synthetic water retention agent (alkali thickening type) 0.10 part Printability improver (water-soluble modified polyamine resin) 0.10 part Fluorescent dye 0.50 part Blue pigment 0. 04 copies

Blended in the above-mentioned solid part by mass, adjusted with sodium hydroxide so as to have a pH of 10.0, adjusted with water so as to have a B-type viscosity of about 500 to 2000 mPa · s, and well stirred with a coating solution did. The pigments abbreviated in Tables 1 to 3 are
Calcium carbonate: Heavy calcium carbonate: Average particle size 0.8μm
Kaolin: Fine kaolin: Average particle size 0.4 μm
Hollow pigment: Polystyrene-based organic hollow pigment: average particle diameter of 1 μm, hollow ratio of 50% by volume
It is. Moreover, the adhesive indicated by the abbreviation is
Synthetic rubber latex A: Styrene-butadiene latex, acrylonitrile mono
10% mer, 80% gel content
Synthetic rubber latex B: Styrene-butadiene latex, acrylonitrile mono
Mer 0%, gel content 60%
Synthetic rubber latex C: Styrene-butadiene latex, acrylonitrile mono
40% mer, 80% gel content
Synthetic rubber latex D: Styrene-butadiene latex, acrylonitrile mono
Mar 55%, gel content 60%
Synthetic rubber latex E: Styrene-butadiene latex, acrylonitrile mono
Mer 5%, gel content 70%
Synthetic rubber latex F: Styrene-butadiene latex, acrylonitrile mono
Mer 50%, gel content 70%
Polyvinyl alcohol A: degree of saponification 98.5%, degree of polymerization 400
Polyvinyl alcohol B: degree of saponification 95%, degree of polymerization 250
Polyvinyl alcohol C: degree of saponification 98.5%, degree of polymerization 1100
Polyvinyl alcohol D: Saponification degree 97%, polymerization degree 300
Polyvinyl alcohol E: Saponification degree 97%, polymerization degree 1500
Modified starch A: Phosphate esterified corn starch,
B-type viscosity of 60 mPa · s at 60 ° C with a solid content concentration of 30%
Modified starch B: oxidized corn starch,
B type viscosity of 250 mPa · at 60 ° C. when the solid content concentration is 30% by mass
s
Modified starch C: phosphate esterified corn starch,
B type viscosity of 200 mPa · at 60 ° C. with a solid content concentration of 30% by mass
s
Modified starch D: hydroxyethyl etherified corn starch,
B-type viscosity of 60 mPa · s at 60 ° C with a solid content concentration of 30%
It is.

About Examples 1-48 and Comparative Examples 1-20, after coating both surfaces by the blade coating method and drying, the calendar process for smoothing was performed. The coating amount was 15 g / m ² per side as a solid content. The calender used a super calender device composed of an elastic roll and a metal roll, and the temperature of the heating metal roll was 60 ° C.

  “CM8060” manufactured by Hewlett-Packard Co. was used as an inkjet printer, and the coating layer strength of the printed part after inkjet printing was evaluated for the inkjet recording paper obtained in each Example and Comparative Example.

<Coating layer strength>
For ink jet recording paper after ink jet printing in an environment of temperature 23 ° C. and humidity 50% RH, a cellophane tape is applied to each solid portion of cyan, magenta, yellow and black, and the tape is slowly peeled off to form a coating layer. The amount broken and transferred to the cellophane tape was visually evaluated with 0 to 10 points. The higher the score, the better, and below 3 is a practical problem.

  The results are shown in Tables 1-3.

<Evaluation results>
In all of Examples 1-48, it was shown that the coating layer strength of the printed part after printing was excellent. Especially about Examples 25-41 and 45-48, the coating layer intensity | strength further improved by using a preferable adhesive agent. Among these, 29-31 and 39-41 which mix | blended 70 parts or more of calcium carbonate and used the preferable adhesive agent showed the very outstanding coating layer intensity | strength. On the other hand, about the comparative examples 1-20 in which the compounding quantity of a calcium carbonate and the compounding quantity of an adhesive agent are not appropriate, the outstanding coating layer intensity | strength was not able to be exhibited. In Comparative Examples 3 to 8, a preferable adhesive was used, but the blending amount of the adhesive was not appropriate, so that an excellent coating layer strength was not exhibited.

  The ink jet recording paper in the present invention is not limited to use as an ink jet recording paper, but can also be used in other printing methods such as wet and dry electrophotography, offset printing, gravure printing, and thermal transfer.

Claims (4)

  In an inkjet recording paper in which a coating layer mainly containing a pigment and an adhesive is provided on at least one side of a support, calcium carbonate is used as a pigment in the coating layer with respect to 100 parts by mass of the total pigment solid content in the coating layer. Inkjet recording paper comprising 60 parts by mass or more, 3-10 parts by mass of a synthetic rubber latex as an adhesive, and 3-10 parts by mass in total of either modified starch or polyvinyl alcohol alone or both. .   The inkjet recording according to claim 1, wherein the synthetic rubber latex is a styrene-butadiene latex, contains 5 to 50% acrylonitrile as a monomer component of the synthetic rubber, and has a gel content of 70% or more. paper.   The modified starch is a corn starch which has been phosphorylated or hydroxyethyl etherized, and after cooking the modified starch, the B-type viscosity at a solid content of 30% by mass and 60 ° C. is 200 mPa · s or less. The inkjet recording paper as described.   The inkjet recording paper according to claim 1, wherein the polyvinyl alcohol has a saponification degree of 97% or more and a polymerization degree of 300 to 1500.