JP2007230174A - Ink jet recording paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recording paper capable of being made by coating a support body, which is coated with a resin coated layer without hydrophilic coat treatment of the resin coated layer, with an aqueous coating liquid for an ink receiving layer, capable of obtaining excellent gloss, having excellent dissolution characteristics of waste ink jet recording paper (including spoilage generated in manufacturing) and easy to treat for recovering. <P>SOLUTION: The ink jet recording paper having the ink receiving layer provided on the support body prepared by coating a base paper with the resin coated layer is characterized in that the support body is coated with the resin coated layer comprising a resin composition, using a polymer aqueous dispersion having the lowest film forming temperature of 30-100°C and a white pigment as essential constituents, having 10-35 pts.mass of the white pigment to 100 pts.mass of a dry solid content, that the support body is coated with the aqueous coating liquid for the ink receiving layer without hydrophilic coat treatment of the resin coated layer, and that the waste ink jet paper (including spoilage generated in manufacturing) has solvability. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording paper, and more particularly, it is possible to apply an aqueous coating liquid for an ink receiving layer on a support coated with the resin coating layer without a hydrophilic coating treatment on the surface of the resin coating layer. The present invention relates to an ink jet recording paper characterized in that it has glossiness and has excellent disaggregation properties with respect to waste paper (including damaged paper at the time of manufacture) of the ink jet recording paper and can be easily recycled. .

  In recent years, with the rapid development of the information industry, various information processing systems have been developed, and recording systems and recording apparatuses suitable for each information system have been developed and adopted. Among them, the ink jet recording method is a method for recording images, characters, and the like by ejecting fine droplets of ink by various operating principles and attaching them to a recording paper such as paper. Since it is compact, no noise, excellent in operability and maintainability, and the apparatus used in such a recording system is easy to record various figures and color images, it has been widely used recently. . Furthermore, an image formed by the multicolor ink jet recording method can obtain a recording that is inferior to a multicolor printing by a plate making method or a print by a color photographic method. Since it is less expensive than the photographic technique, it is widely applied to the field of full-color image recording.

  Efforts have been made from the aspect of apparatus and ink composition for the purpose of using high-quality paper and coated paper used for normal printing and writing as recording paper used in this ink jet recording system. However, with the improvement of the performance of the ink jet recording apparatus and the expansion of applications such as high speed and high definition of the apparatus or full color, more advanced characteristics have been required for the recording paper.

  As inkjet recording paper, the density of the printed dots is high, the color tone is bright and vivid, the ink absorbs quickly and the printed dots do not flow or bleed, and the printed dots spread laterally. Therefore, high image reproducibility is required such that the image is not larger than necessary and the periphery is smooth and unblurred.

  In particular, due to the recent spread of digital cameras, the ink jet recording method has been generally recognized as a conventional silver salt recording method, that is, an alternative recording method for photographs. In order to make it closer to a photograph, the same resin-coated paper as the support for photographic printing paper has come to be used for the support for inkjet recording paper. Here, the resin-coated paper is produced by heating and melting a pellet-shaped resin with an extruder and extruding it onto a base material such as paper to perform coating.

  Inkjet recording paper using resin-coated paper is subjected to activation treatment such as corona discharge treatment, flame treatment, glow discharge treatment, or plasma treatment on the surface of the resin coating layer, and the ink-receiving layer is formed on the resin coating layer after treatment. A water-based coating solution is applied, and when applying the ink-receiving layer aqueous coating solution, the affinity with the ink-receiving layer, the elimination of coating unevenness, and a gloss that is close to a photograph of the ink-receiving layer surface after coating For the purpose of imparting a feeling, an anchor coat layer was previously applied to the surface of the resin coating layer (see, for example, Patent Documents 1 and 2).

  As a coating solution for the anchor coat layer, gelatin is a main component, and in addition, a hardener, a surfactant, a thickener, a white pigment, a matting agent, an antifoaming agent, an antistatic agent, if necessary. Those containing additives such as antifoggants have been used.

  As a method of providing the anchor coat layer on the resin-coated surface, after the resin is coated on the traveling base paper surface, the anchor coat layer coating liquid is applied and dried on the resin-coated surface before winding. For example, an on-machine method in which the anchor coat layer is provided, or an off-machine method in which the resin-coated paper is wound up and then stored as necessary, and then used to provide an anchor coat layer. As an anchor coat layer coating device, an air knife coater, roll coater, bar coater, wire bar coater, blade coater, slide hopper coater, curtain coater, gravure coater, flexographic gravure coater, and combinations thereof are used. Has been.

However, in the coating method as described above, the coating amount of the anchor coat layer is as small as 40 to 300 mg / m ² (dry solid content), and the hydrophilicity of the resin coating layer surface is poor and high-speed coating is difficult. In addition, a non-uniform surface called coating unevenness was likely to occur on the anchor coat layer surface. In addition, when high-speed coating is performed using an air knife coater, it is difficult to remove bubbles mixed in the coating liquid of the anchor coat layer. Furthermore, with a gravure coater, phenomena such as coating omission due to plate clogging are likely to occur. It was a big factor to inhibit.

  Furthermore, there is a disaggregation process for separating the coated resin (laminate part) from the base paper in the recycling process of waste paper (also called laminated waste paper) in resin-coated paper and waste paper at the time of manufacture. As a method, for example, a papermaking raw material including waste paper of resin-coated paper is crushed into a piece of paper passing through the strainer by a pulper equipped with a strainer having a hole diameter of 10 to 40 mm, and hydrated and swollen in a retention tower for 10 hours or more. A method is disclosed in which the bond between the paper piece and the resin-coated piece is weakened and the resin-coated piece is removed on a screen having a hole diameter of 3 to 6 mm (see, for example, Patent Document 3).

  Also, after dissociating the finely cut waste paper of the resin-coated paper and concentrating the obtained pulp slurry, mechanical shearing force is applied, and then the resin is coated with dust removing means such as a hole screen or slit screen. A method of removing a piece is disclosed. And in this method, the waste paper of resin-coated paper is cut smaller than 1 cm × 10 cm. The reason for cutting in such a small amount is that the large resin-coated pieces clog the holes and slits of the dust removing means by collecting large and small resin-coated pieces (plastic film) from the actual waste paper of the resin-coated paper. (For example, refer to Patent Document 4).

However, according to Patent Document 3, there is a problem that a special process of hydration and swelling for weakening the bond between the paper piece and the resin-coated piece is required. Further, according to Patent Document 4, since the waste paper of resin-coated paper is smaller than 1 cm × 10 cm, that is, finely cut, the refined resin-coated piece passes through the dust removing means, and the used waste paper pulp is obtained. It may remain as a foreign object. In order to remove the finer resin-coated pieces, it may be possible to reduce the size of the dust removal means or reduce the slit width, but this causes the problem of clogging of the eye holes and slits. Besides, there is a problem that the equipment load becomes large and the equipment becomes large.
JP-A-1-102551 Japanese Patent Laid-Open No. 1-166035 JP 60-134089 A Japanese Patent Laid-Open No. 10-096182

  The object of the present invention is to provide a corona discharge treatment, flame treatment, glow discharge on the resin-coated surface of a resin-coated paper which has been conventionally heated and melted with an extruder and extruded onto a substrate such as paper. Ink receiving layer without activation treatment of resin coating layer surface, for treatment or activation treatment such as plasma treatment, and applying water-based coating liquid for ink receiving layer on treated resin coating layer An ink jet recording paper that can be applied with a water-based coating liquid for use, and has excellent disaggregation properties with respect to the waste paper of the resin-coated paper and waste ink jet recording paper using the resin-coated paper, and can be easily recycled. To do.

  As a result of intensive studies in view of the above, the present inventors have made it possible to apply an aqueous coating liquid for an ink receiving layer on a support coated with the resin coating layer without the hydrophilic coating treatment on the surface of the resin coating layer. Inventive ink jet recording paper has been obtained that has high glossiness, has excellent disaggregation properties with respect to waste paper (including damaged paper at the time of manufacture) of the ink jet recording paper, and can be easily recycled.

That is, this invention makes the following a summary.
(1) In an ink jet recording paper in which an ink receiving layer is provided on a support in which a base paper is coated with a resin coating layer, the support is an essential component, and an aqueous polymer dispersion having a minimum film-forming temperature of 30 to 100 ° C. and white Using the pigment, the aqueous polymer dispersion is obtained by coating the resin coating layer made of a resin composition containing 10 to 35 parts by weight of a white pigment with respect to 100 parts by weight of a dry solid, on the support. Is formed by coating the surface of the resin coating layer with an aqueous coating liquid for an ink receiving layer without the hydrophilic coating treatment, and used paper for ink jet recording paper (including damaged paper at the time of manufacture) has disaggregation properties. An inkjet recording paper characterized by the above.
(2) Polymer aqueous dispersion is polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyvinyl acetate, polystyrene, ethylene copolymer, acrylic copolymer, vinyl chloride copolymer, styrene / butadiene system The inkjet recording paper according to (1) above, which is at least one selected from the group consisting of a copolymer, a methacrylic acid / butadiene copolymer, an ethylene ionomer base resin, and a styrene ionomer base resin.
(3) The ethylene ionomer base resin is an ethylene / acrylic acid copolymer, an ethylene / methacrylic acid copolymer, an ethylene / maleic acid copolymer, an ethylene / fumaric acid copolymer or an ethylene / maleic anhydride copolymer. The inkjet recording paper as described in (2) above.
(4) The inkjet recording paper according to the above (3), wherein the ethylene ionomer base resin is an ethylene / acrylic acid copolymer or an ethylene / methacrylic acid copolymer.
(5) Styrene ionomer base resin is a styrene / acrylic acid copolymer, styrene / methacrylic acid copolymer, styrene / maleic acid copolymer, styrene / fumaric acid copolymer or styrene / maleic anhydride copolymer. The inkjet recording paper as described in (2) above.
(6) White pigment is calcium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium oxide, zinc oxide, satin white, aluminum silicate, calcium silicate, magnesium silicate, synthetic silica, aluminum hydroxide, alumina, styrene The inkjet recording paper according to the above (1), which is at least one selected from the group consisting of a series resin, an acrylic resin, polyethylene, a urea resin, and a melamine resin.

  According to the present invention, an ink receiving layer is provided on a support in which a base paper is coated with a resin coating layer, and the aqueous coating liquid for the ink receiving layer is applied onto the support without the hydrophilic coating treatment on the surface of the resin coating layer. An inkjet recording paper that can be processed, has excellent gloss, has excellent disaggregation properties with respect to waste paper (including damaged paper at the time of manufacture), and can be easily recycled. Obtainable.

  Hereinafter, the ink jet recording paper of the present invention will be specifically described.

  The ink jet recording paper of the present invention is comparable to a resin-coated paper that is a support for a photographic printing paper produced by heating and melting a pellet-like resin with an extruder and extruding the resin onto a base material such as paper. It is a support having a resin coating layer and has excellent gloss.

  That is, firstly, the ink jet recording paper of the present invention has an ink receiving layer provided on a support in which a base paper is coated with a resin coating layer. It is possible to apply an aqueous coating liquid for an ink receiving layer.

  Secondly, the ink jet recording paper of the present invention is disaggregated simultaneously with general waste paper without separately disassembling the waste paper at the time of manufacture and the waste paper of the ink jet recording paper (including the waste paper at the time of manufacture). Can be easily performed.

  As described above, in conventional resin-coated paper, a pellet-shaped resin is heated and melted to perform extrusion coating, and when applying a water-based ink-receiving layer coating liquid to the resin coating layer, corona discharge treatment, Apply an activation treatment such as flame treatment, glow discharge treatment, or plasma treatment, and then apply an anchor coat layer coating solution mainly composed of gelatin to improve the water-repellent resin coating layer surface to a hydrophilic coating surface There was a need to do.

  In the ink jet recording paper of the present invention, a base material is provided with a resin coating layer as a support, and a water-based ink receiving layer coating liquid can be applied as it is without subjecting the resin coating layer surface to a hydrophilic treatment. There are features.

  In the present invention, the resin composition of the resin coating layer applied to the base paper is a polymer aqueous dispersion and a white pigment having a minimum film forming temperature of 30 to 100 ° C. as essential components, and the polymer aqueous dispersion is dried. By using 10 to 35 parts by weight of a white pigment with respect to 100 parts by weight of the solid content and applying this to the base paper, the surface of the resin coating layer can be made hydrophilic.

  The reason that the surface of the resin coating layer in the present invention can be hydrophilized is not fully known, but one uses a polymer aqueous dispersion having a minimum film forming temperature of 30 to 100 ° C. It is considered that the polymer aqueous dispersion is mixed with the white pigment at a specific ratio. That is, the uniform dispersion of the white pigment is easy due to the polymer aqueous dispersion, and the coating on the base paper can also be applied using conventional techniques, and the surface of the resin coating layer coated on the base paper is close to the surface layer. Can hold a white pigment in a state of being complimented, and can form a smooth film by limiting the minimum film-forming temperature of the polymer aqueous dispersion itself to 30 to 100 ° C. It is inferred that hydrophilicity due to the white pigment on the surface of the coating layer appears.

  In particular, in the present invention, it was revealed that the hydrophilic effect of the resin coating layer surface is further improved by using an ionomer base resin as the polymer aqueous dispersion. An ionomer base resin is, for example, an ionic polymer having a special structure in which molecules such as ethylene / methacrylic acid copolymer and ethylene / acrylic acid copolymer are intermolecularly bonded with metal ions such as sodium and zinc. It means a molecule, and it is presumed that the hydrophilicity of the surface of the resin coating layer appears due to structural metal ions.

  In the present invention, as the polymer aqueous dispersion, it is one condition in the present invention that the minimum film-forming temperature is 30 to 100 ° C. The temperature regulation here refers to the application of the resin coating layer coating liquid mainly composed of an aqueous polymer dispersion and a white pigment, and the resin coating layer coating liquid is applied and dried through a dryer. When forming, the temperature is determined in consideration of the balance between the coating speed and the drying capacity of the dryer, and the resin coating layer is sufficient for drying after coating when coating with normal coating equipment Since the coating is formed, it is defined according to this condition. Here, when the minimum film-forming temperature is higher than 100 ° C., it is not preferable because the film formation is insufficient and at the same time poor drying when drying after coating. On the other hand, when the temperature is lower than 30 ° C., the film-forming property is excellent, but the formed film is not preferable because of stickiness and blocking.

  Here, the minimum film-forming temperature is a temperature measured by a temperature gradient plate method described in ISO standard 2115 using a thermal gradient test apparatus, and specifically, a temperature gradient test apparatus (Yoshimitsu Seiki Co., Ltd.). A temperature gradient is set by placing a PET film having a thickness of 25 μm on a stainless steel plate manufactured by YOSIMITSU MFT-1), and then an emulsion (in the present invention) is formed on the PET film with a stable temperature gradient to a thickness of 0.3 mm. Then, a polymer aqueous dispersion) is applied, and immediately after the application, the basket containing silica gel is placed on a plate and covered with a transparent plastic lid. After the coating film has dried, the temperature at the boundary between the uniform continuous film portion and the cloudy portion is read, and this is set as the minimum film forming temperature.

  Examples of the aqueous polymer dispersion used in the present invention include polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyvinyl acetate, polystyrene, an ethylene copolymer, an acrylic copolymer, a vinyl chloride copolymer, and styrene. -It is at least 1 sort (s) chosen from the group which consists of a butadiene-type copolymer, a methacrylic acid butadiene copolymer, an ethylene-type ionomer base resin, and a styrene-type ionomer base resin.

  Examples of the ethylene ionomer base resin include an ethylene / acrylic acid copolymer, an ethylene / methacrylic acid copolymer, an ethylene / maleic acid copolymer, an ethylene / fumaric acid copolymer, or an ethylene / maleic anhydride copolymer. Can be mentioned. An ethylene / acrylic acid copolymer or an ethylene / methacrylic acid copolymer is preferred.

  Styrene ionomer base resins include styrene / acrylic acid copolymers, styrene / methacrylic acid copolymers, styrene / maleic acid copolymers, styrene / fumaric acid copolymers or styrene / maleic anhydride copolymers. It is done.

In the ionomer base resin, the metal ions to be neutralized include metal ions having 1 to 3 valences, particularly 1 to 3 atoms in groups I, II, III, IV and VII in the periodic table. It is a metal ion having a valence. For example, Na ⁺ , K ⁺ , Li ⁺ , Cs ⁺ , Ag ⁺ , Hg ⁺ , Cu ⁺ , Be ⁺⁺ , Mg ⁺⁺ , Ca ⁺⁺ , Sr ⁺⁺ , Ba ⁺⁺ , Cu ⁺⁺ , Cd ⁺⁺ , Hg ⁺⁺ , Sn ^{+ pb ++, Fe ++, Co ++} , Ni ++, Zn ++, Al +++, Sc +++ Fe +++, or ^{Y +++} and the like. These metal ions may be mixed components of two or more kinds, or may be mixed components with ammonium ions and various amine ions. Among these metal ions, Zn ⁺⁺ or Na ⁺ is particularly preferable.

  For the white pigment used in combination with the above polymer aqueous dispersion, calcium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium oxide, zinc oxide, satin white, aluminum silicate, calcium silicate, magnesium silicate, synthetic silica Inorganic pigments such as aluminum hydroxide and alumina; or one or a mixture of two or more organic pigments such as styrene resin, acrylic resin, polyethylene, urea resin and melamine resin, and high for coated resin coating layers In order to give whiteness, at least one selected from the group consisting of titanium oxide, zinc oxide, and alumina is preferable.

  In the present invention, the mixing ratio of the polymer aqueous dispersion and the white pigment is 10 to 35 parts by mass of the white pigment with respect to 100 parts by mass of the dry solid content of the polymer aqueous dispersion. Here, when the ratio of the white pigment is less than 10 parts by mass, the aqueous coating liquid for ink receiving layer cannot be applied to the coated resin coating layer surface. On the other hand, if it exceeds 35 parts by mass, the aqueous coating liquid for ink-receiving layer can be applied to the surface of the resin coating layer, but there is a drawback that the film-forming property of the polymer aqueous dispersion itself is inferior.

  As the coating composition used for the resin coating layer in the present invention, in addition to the above-described polymer aqueous dispersion and white pigment, examples of water-soluble natural polymer resins include methyl cellulose, methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, hydroxy Cellulose adhesives such as ethyl cellulose, starch and modified products thereof, gelatin and modified products thereof, casein, pullulan, gum arabic, and albumin, and water-soluble synthetic polymers such as polyvinyl alcohol and modified products thereof, poly (Meth) acrylic acid derivatives, polyethylene glycol, polyethylene oxide, polyvinyl pyrrolidone, polyacrylamide and the like and derivatives thereof may be used in combination.

  Furthermore, the coating composition used for the resin coating layer includes water-resistant agents such as glyoxal, dimethylol urea, trimethylol melamine, blue pigments and dyes such as cobalt blue, ultramarine blue, ceria blue, and phthalocyanine blue, and cobalt violet. , Fast Violet, Manganese Violet and other magenta pigments and dyes, fluorescent brighteners, UV absorbers, pigment dispersants, thickeners, fluidity improvers, antifoaming agents, etc. Can be contained.

About the coating amount of the coating composition which forms the resin coating layer in this invention, it is 4-70 g / m < ² >, Preferably it is 6-45 g / m < ² >, Most preferably, it is 10-40 g / m < ² >.

  Examples of the resin coating layer coating apparatus in the present invention include conventionally known air knife coaters, curtain coaters, die coaters, blade coaters, gate roll coaters, bar coaters, rod coaters, roll coaters, bill blade coaters, and short dwell blade coaters. It can be coated on the base paper by various devices such as a size press. In addition, after coating, smoothing can be performed using a calendar device such as a machine calendar, a TG calendar, a super calendar, or a soft calendar.

  Furthermore, the ink jet recording paper of the present invention has excellent disaggregation properties with respect to the waste paper of the ink jet recording paper (including damaged paper at the time of manufacture), and can be easily recycled. This will be described below.

  Conventionally, a method of recycling a resin-coated paper waste paper that has been extrusion-coated by heating and melting a pellet-shaped resin is to peel the resin-coated paper from the paper without making it fine, and remove the resin-coated layer portion with a screen or the like. The method is adopted. When the resin-coated paper is miniaturized, it passes through a screen or the like, and therefore it is naturally desirable not to make it fine. However, punching scraps after punching with resin, punching scraps of resin-coated paper, etc. are actually generated industrially. Also, in the collection of used resin-coated paper, shredder and There are many cases where the size is reduced by a cutter.

  On the other hand, for the ink jet recording paper of the present invention, a resin coating layer obtained by subjecting a conventional pellet-shaped resin to heat-melting and extrusion coating by using a polymer aqueous dispersion as the coating composition of the resin coating layer. Compared to the ink jet recording paper provided with the above, it has excellent disaggregation properties and can be easily regenerated. This is because when the aqueous polymer dispersion and the white pigment are mixed in a specific ratio and applied aqueous on the base paper, it has film-forming properties as a resin coating layer. This is considered to be caused by maintaining a balance between disintegration and disintegration in an appropriate state.

  In the present invention, the pulper used in the disaggregation step is not particularly limited as long as it is usually used in the paper industry. For example, a low concentration pulper, a high concentration pulper, a separator or the like can be used. As the low concentration pulper, a hydra pulper, a rotor pulper, a horizontal pulper, or the like can be used.

  In the disaggregation step, the pulp concentration is disaggregated at 3 to 10% by mass, and the process proceeds to the next concentration step. In a concentration process, it concentrates so that a pulp density | concentration may be 15 mass% or more, and it carries out by 20-40 mass% in the next process so that a shearing force can be easily made to a pulp slurry.

  In the step of applying a mechanical shearing force, heating is performed using a screw type single or twin screw mixer, a disperser, a kneader, a mica processor, and the like, and the mechanical shearing force is applied in a softened state of the coated resin piece. This is diluted, the pulp is taken out by the screen, and the coating resin piece is removed by the screen.

  However, the waste paper of the inkjet recording paper according to the present invention (including waste paper at the time of manufacture) is processed in a disaggregation process without being subdivided, and is easily pulped by a selective screen through mechanical shearing. And the coating resin can be separated and removed.

  In the ink jet recording paper of the present invention, an ink receiving layer coating liquid containing inorganic ultrafine particles is applied onto a resin coating layer provided on a base paper.

  The inorganic ultrafine particles used in the present invention are inorganic fine particles having a primary particle diameter of 100 nm or less. For example, pseudoboehmite sol which is an alumina hydrate disclosed in JP-A-3-285815, JP-A-4-92183, JP-A-4267180, JP-A-4-275717, etc. Colloidal silica as described in JP-A-188183, 63-178074, JP-A-5-51470, etc., and silica / alumina hybrid sol as described in JP-A-62-2286787 Silica sol in which gas phase method silica is dispersed with a high-speed homogenizer as described in JP-A-10-119423 and JP-A-10-217601, smectite clay such as hectite and montmorillonite, zirconia Sol, chromia sol, yttria sol, ceria sol, iron oxide sol, di Konzoru, can be cited as a typical and antimony oxide sol.

  Among these inorganic ultrafine particles, gas phase method silica ultrafine particles or alumina hydrate can be preferably used.

Silica fine particles are fine particles composed of SiO ₂ 93% or more, Al ₂ O ₃ about 5% or less, Na ₂ O about 5% or less on a dry basis. There is crystalline silica. As methods for producing amorphous silica fine particles, there are a liquid phase method, a pulverized solid phase method, a crystallization solid phase method, and a gas phase method. The liquid phase method is a production method in which a silicic acid compound or the like existing in a so-called liquid is precipitated in a solid state by a chemical change or a physical change. The pulverized solid phase method is a method of mechanically pulverizing silica solids, and the crystallization solid phase method is a production method utilizing melting, phase transition of solids, or the like. The gas phase method is a production method by pyrolysis of vapor of a volatile metal compound, heating and evaporation of raw materials, cooling of a generated gas phase species, and condensation.

  As for the amorphous silica fine particles synthesized by the vapor phase method, ultrafine silica particles having an average primary particle diameter of 3 to 20 nm are preferable, and those having a primary particle diameter of 4 to 10 nm are particularly preferable. Moreover, 10-400 nm is preferable in the secondary particle diameter which these connected. As a product marketed as amorphous silica fine particles synthesized by this vapor phase method, Aerosil (Tegusa Co., Ltd.) can be mentioned.

  The vapor phase method silica is obtained by adding silica fine particles having the above primary particle diameter to water and dispersing with a high-speed homogenizer or the like to disperse the average secondary particle diameter to 400 nm or less, preferably 200 nm or less.

Alumina hydrate is expressed as Al ₂ O ₃ · nH ₂ O. Alumina hydrate is dipsite, vialite, norstrandite, boehmite, boehmite gel (pseudoboehmite gel) depending on the composition and crystal form. ), Diaspore, amorphous amorphous, and the like. Among them, when the value of n of Al ₂ O ₃ .nH ₂ O is 1, it represents boehmite-structured alumina hydrate, and when n is less than 1 to 3, it represents pseudo-boehmite-structured alumina hydrate. , N is 3 or more, it represents an amorphous alumina hydrate.

  The shape of the alumina hydrate may be any of a flat plate shape, a fiber shape, a needle shape, a spherical shape, a rod shape, and the like, and a preferable shape is a flat plate shape from the viewpoint of ink absorbability. The plate-like alumina hydrate has an average aspect ratio of 3 to 8, and preferably an average aspect ratio of 3 to 6.

  Commercially available alumina hydrate can also be suitably used for the inkjet recording paper in the present invention. One example is given below, but the present invention is not limited thereto. For example, as alumina hydrate, cataloid AS-1, cataloid AS-2, cataloid AS-3 (above, manufactured by Catalytic Chemical Industry Co., Ltd.), alumina sol 100, alumina sol 200, alumina sol 520 (above, manufactured by Nissan Chemical Industries, Ltd.) , M-200 (manufactured by Mizusawa Chemical Co., Ltd.), aluminum sol 10, aluminum sol 20, aluminum sol 132, aluminum sol 132S, aluminum sol SH5, aluminum sol CSA55, aluminum sol SV102, aluminum sol SB52 (manufactured by Kawaken Fine Chemical Co., Ltd.) Can do.

  In the present invention, a water-soluble polymer compound may be added as a binder for the inorganic ultrafine particles used. The polymer compound used in the present invention is a compound having an affinity for ink as a constituent component of the ink receiving layer. Examples of water-soluble polymer compounds include cellulose-based binders such as methylcellulose, methylhydroxyethylcellulose, methylhydroxypropylcellulose, and hydroxyethylcellulose, starch and modified products thereof, gelatin and modified products thereof, casein, pullulan, gum arabic, and albumin. Latex such as natural polymer resins and derivatives thereof, polyvinyl alcohol and modified products thereof, styrene / butadiene copolymer, styrene / acrylic copolymer, methyl methacrylate / butadiene copolymer, ethylene / vinyl acetate copolymer, etc. And emulsions, vinyl polymers such as polyacrylamide and polyvinylpyrrolidone, polyethyleneimine, polypropylene glycol, polyethylene glycol, maleic anhydride Coalescence and the like. Polyvinyl alcohol is preferable.

  These binders may be used alone or in combination of two or more, and are added in an amount of 2 to 50% by mass, preferably 5 to 30% by mass, based on the inorganic ultrafine particles. When the amount is less than the above range, the strength of the coating film becomes weak. When the amount exceeds the above range, the ink absorbability is lowered.

  As a method of applying the ink receiving layer coating liquid in the present invention, conventionally known air knife coater, curtain coater, die coater, blade coater, gate roll coater, bar coater, rod coater, roll coater, bill blade coater, short It can be coated on the base paper by various devices such as a dwell blade coater and a size press. In addition, after application of the ink receiving layer, smoothing can be performed using a calendar device such as a machine calendar, a TG calendar, a super calendar, or a soft calendar.

  In the present invention, the layer structure of the ink receiving layer may be a single layer or a laminated structure. In the case of a laminated structure, all the layers may be layers having the same composition, or may be a laminated structure with layers composed of other components.

In the present invention, the coating amount of the ink receiving layer coating liquid containing inorganic ultrafine particles, 5 g / ^{m 2} or more as a solid basis, preferably 10 to 30 g / ^{m 2,} particularly preferably 10 to 20 g / m ² . Although it depends on the amount of voids, the thickness is preferably 10 to 30 μm.

  Further, the ink-receiving layer coating liquid used in the present invention may include a surfactant, an inorganic pigment, a coloring dye, a coloring pigment, an ink dye fixing agent (cationic resin), an ultraviolet absorber, and an antioxidant as necessary. Various known additives such as pigment dispersants, antifoaming agents, leveling agents, preservatives, optical brighteners, viscosity stabilizers, pH adjusters, and hardening agents can be added.

  The base paper surface opposite to the ink receiving layer surface of the ink jet recording paper in the present invention is coated with the resin coating layer coating composition or the polymer aqueous dispersion itself used for the resin coating layer to prevent curling. A back coat layer may be provided as a countermeasure.

  For the base paper used in the present invention, natural pulp is the main component, normal bleaching treatment such as chlorine, hypochlorite, chlorine dioxide, and alkali extraction or alkali treatment, and hydrogen peroxide, oxygen as necessary. Coniferous pulp, hardwood pulp, conifer hardwood mixed pulp wood pulp that has been subjected to oxidative bleaching treatment, enzyme bleaching, etc., and combinations thereof, and various types of kraft pulp, sulfite pulp, soda pulp, etc. Things can be used. Furthermore, waste paper such as waste newspaper, imitation waste paper, colored waste paper, and magazine waste paper can be blended.

Although there is no restriction | limiting in particular about the thickness of the base paper used in this invention, The thing of 80-250 g / m < ² > is preferable as the basic weight.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In addition, unless otherwise indicated, all the parts and% in an Example show the mass part and mass% by dry solid content.

Example 1
Using high-quality paper with a basis weight of 170 g / m ² as the base paper, 100 parts of ethylene / vinyl acetate copolymer (trade name: Sumikaflex 850HQ, manufactured by Sumitomo Chemical Co., Ltd.) having a minimum film-forming temperature of 40 ° C., 15 parts of titanium oxide A coating solution for a 30% resin coating layer comprising 2.5 parts of polyvinyl alcohol and 1.5 parts of glyoxal is prepared, and an air knife coater is applied so that the coating amount becomes 10 g / m ² (dry solid content). The support body of Example 1 which coated and dried using the machine calendar finish and coated the resin coating layer was manufactured. Subsequently, 70 parts of synthetic amorphous silica (Fan Seal X37B, manufactured by Tokuyama Soda Co., Ltd.), 30 parts of vapor phase silica (Aerosil 200, manufactured by Nippon Aerosil Co., Ltd.), and cationic dye fixing agent (ink receiving layer coating liquid) A composition comprising 10 parts of Sumire's Resin 1001, manufactured by Sumitomo Chemical Co., Ltd.) and 20 parts of polyvinyl alcohol (PVA117, manufactured by Kuraray Co., Ltd.) was prepared to a solid content concentration of 15%, and this was applied at a coating amount of 10 g / The ink jet recording paper of Example 1 was produced, which was coated and dried using an air knife coater so as to have m ² (dry solid content), machine calendered, and coated with an ink receiving layer coating liquid.

(Example 2)
An ink jet recording paper of Example 2 was produced in the same manner as in Example 1 except that the titanium oxide in the coating solution for resin coating layer in Example 1 was replaced with 10 parts.

(Example 3)
An ink jet recording paper of Example 3 was produced in the same manner as in Example 1 except that 35 parts of titanium oxide in the coating solution for resin coating layer in Example 1 was replaced with 35 parts.

(Comparative Example 1)
An ink jet recording paper of Comparative Example 1 was produced in the same manner as in Example 1 except that the titanium oxide in the resin coating layer coating liquid formulation in Example 1 was replaced with 5 parts.

(Comparative Example 2)
An inkjet recording paper of Comparative Example 2 was produced in the same manner as in Example 1 except that 40 parts of titanium oxide in the coating liquid composition for resin coating layer in Example 1 was replaced.

Example 4
In Example 1, an ethylene / vinyl acetate copolymer having a minimum film-forming temperature of 40 ° C. in the coating composition for the resin coating layer was changed to an ethylene / vinyl acetate copolymer having a minimum film-forming temperature of 70 ° C. (trade name: Aquatex HA- Inkjet recording paper of Example 4 was produced in the same manner as in Example 1 except that 1100, manufactured by Rika Bond Co., Ltd. was used.

(Example 5)
In Example 1, an ethylene / vinyl acetate copolymer having a minimum film-forming temperature of 40 ° C. in the coating composition for the resin coating layer was replaced with an ethylene / vinyl chloride copolymer having a minimum film-forming temperature of 30 ° C. (trade name: SUMIKAFLEX SE- Inkjet recording paper of Example 5 was produced in the same manner as in Example 1 except that it was changed to 1210 (manufactured by Sumitomo Chemical Co., Ltd.).

(Example 6)
In Example 1, an ethylene / vinyl acetate copolymer having a minimum film-forming temperature of 40 ° C. in the formulation of the coating solution for the resin coating layer was replaced with a styrene / methacrylic acid copolymer having a minimum film-forming temperature of 100 ° C. (trade names: Movinyl 972, Nichigo) An ink jet recording paper of Example 6 was produced in the same manner as in Example 1 except that it was replaced with (Movinyl).

(Example 7)
In Example 1, an ethylene / vinyl acetate copolymer having a minimum film-forming temperature of 40 ° C. during blending of the coating solution for the resin coating layer was changed to an ethylene / methacrylic acid copolymer ionomer base resin having a minimum film-forming temperature of 40 ° C. (trade name: High Milan). Inkjet recording paper of Example 7 was produced in the same manner as Example 1 except that it was changed to Mitsui DuPont Polychemical Co., Ltd.

(Comparative Example 3)
In Example 1, an ethylene / vinyl acetate copolymer having a minimum film-forming temperature of 40 ° C. in the resin coating layer coating composition was mixed with an acrylic resin (trade name: Ricabond ES-21, Chuo Rika Kogyo Co., Ltd.). An ink jet recording paper of Comparative Example 3 was produced in the same manner as in Example 1 except that it was changed to (manufactured).

(Comparative Example 4)
In Example 1, an ethylene / vinyl acetate copolymer having a minimum film-forming temperature of 40 ° C. during blending of the coating solution for the resin coating layer was made of an acrylic resin (trade name: Ricabond ES-90, Chuo Rika Kogyo Co., Ltd.). An ink jet recording paper of Comparative Example 4 was produced in the same manner as in Example 1 except that it was changed to (manufactured).

(Example 8)
In Example 1, an ethylene / vinyl acetate copolymer having a minimum film-forming temperature of 40 ° C. during the blending of the coating solution for the resin coating layer was made of an acrylic resin having a minimum film-forming temperature of 50 ° C. (trade name: Mobile 742N, manufactured by Nichigo / Movinyl) In addition, an inkjet recording paper of Example 8 was produced in the same manner as in Example 1 except that the titanium oxide was replaced with aluminum hydroxide.

Example 9
In Example 1, an ethylene / vinyl acetate copolymer having a minimum film-forming temperature of 40 ° C. during the blending of the coating solution for the resin coating layer was made of an acrylic resin having a minimum film-forming temperature of 50 ° C. (trade name: Mobile 742N, manufactured by Nichigo / Movinyl) In addition, an inkjet recording paper of Example 9 was produced in the same manner as in Example 1 except that 15 parts of titanium oxide was replaced with 10 parts of aluminum hydroxide.

(Example 10)
In Example 1, an ethylene / vinyl acetate copolymer having a minimum film-forming temperature of 40 ° C. during the blending of the coating solution for the resin coating layer was made of an acrylic resin having a minimum film-forming temperature of 50 ° C. (trade name: Mobile 742N, manufactured by Nichigo / Movinyl) In addition, an ink jet recording paper of Example 10 was produced in the same manner as in Example 1 except that 15 parts of titanium oxide was replaced with 35 parts of aluminum hydroxide.

  The supports and ink jet recording paper prepared in Examples 1 to 10 and Comparative Examples 1 to 4 were evaluated by the following evaluation methods, and the results are shown in Table 1. For comparison, a commercially available laminate-type ink jet recording paper was used as the target example 1.

<Wettability>
In accordance with “Plastic-Film and Paper-Wetting Tension Test Method”, a standard test room atmosphere (JIS K 7100) having a temperature of 23 ° C. and a relative humidity of 50% with respect to the wetting tension of the surface of the support produced in Examples and Comparative Examples. Under the above, it measured using the "wet tension test liquid" by the pure chemical company by JISK6768. The unit of wetting tension is mN / m. Here, if it is 40 mN / m or more, aqueous coating, that is, coating of the ink-receiving layer coating solution can be performed.

<Glossiness>
The glossiness was measured by measuring the 75 ° specular glossiness according to JIS P-8142 after conditioning the sample for 24 hours in an environment of 20 ° C. and 65% RH. In the measurement, the surface of the inkjet recording paper coated with the support (resin-coated paper) and the ink receiving layer coating liquid before the ink receiving layer coating liquid was applied was measured. In the present invention, the glossiness is desirably 80% or more as a support and 75% or more as an inkjet recording paper.

<Disaggregation>
Standard dissociator shown in JIS P 8209 (1976) Pulp Test Handmade Paper Preparation Method by adding 2% by mass to warm water heated to 45 ° C. on an inkjet recording paper cut into 1 cm square Using a Tappi standard disintegrator, the mixture was stirred and dispersed at 3000 rpm for 15 minutes, and the dispersion state of the slurry was observed. Then, the obtained slurry was passed through a slit screen having a width of 0.15 mm, and the presence or absence of undissolved material was visually observed on the screen to evaluate the disintegration property.

<Evaluation>
About wettability, in Examples 1-10, the polymer film aqueous dispersion whose minimum film forming temperature in this invention is 30-100 degreeC is used, and a white pigment is 10-10 mass parts with respect to 100 mass parts of this polymer aqueous dispersion. If it is 35 parts by mass, the wettability index is 40 mN / m or more in any of the examples, and the ink-receiving layer coating liquid can be applied to the support without any problem. In Example 7 using a methacrylic acid ionomer base resin, the wettability was excellent and the wetness index was 53 mN / m. On the other hand, when the content of the white pigment in Comparative Example 1 is less than 10 parts by mass, the wetting index is less than 40 mN / m, and a satisfactory repellency phenomenon occurs during water-based coating of the ink-receiving layer coating liquid, resulting in satisfactory ink jet recording. When no paper is obtained and the content of the white pigment in Comparative Example 2 exceeds 35 parts by mass, a wetting index of 40 mN / m or more can be obtained, but sufficient film forming properties can be obtained. I can't. Further, in Comparative Example 3, the minimum film-forming temperature of the polymer aqueous dispersion is less than the specified range, and the support surface after application of the ink receiving layer coating liquid and drying is sticky. Comparative Example 4 In this case, the minimum film-forming temperature of the aqueous polymer dispersion was higher than the specified range, and the coating layer was not sufficiently dried, resulting in poor film formation.

  Further, the glossiness was measured for the support provided with the resin coating layer and the ink jet recording paper. In any of the examples, the glossiness of the support and the ink jet recording paper was as high as 80% or more. It was. On the other hand, in Comparative Example 2, the content of the white pigment in the polymer aqueous dispersion was large, the film formability was inferior, and the glossiness was also low. In Comparative Example 3, since the minimum film-forming temperature of the polymer aqueous dispersion is less than the specified range, the support surface after application of the ink-receiving layer coating liquid and drying is sticky, Along with this, the glossiness was also low. Furthermore, in Comparative Example 4, although the minimum film-forming temperature of the polymer aqueous dispersion is higher than the specified range, the resin coating layer is insufficiently dried, and as a result, the glossiness is also satisfactory. It was not obtained.

  Further, the disaggregation was performed using the ink jet recording papers according to the examples and comparative examples. In Examples 1 to 10, there was no undissolved material, and satisfactory results were obtained. On the other hand, Comparative Example 2 is inferior in film formability when the ink-receiving layer coating solution is applied, and Comparative Example 3 defines the minimum film-forming temperature of the polymer aqueous dispersion when applying the ink-receiving layer coating solution. The surface of the obtained ink receiving layer was sticky, and a small amount of undissolved material remained. Further, in Comparative Example 4, although a high polymer aqueous dispersion having a minimum film forming temperature exceeding the specified range was used, the resin coating layer surface of the support after coating and drying was poorly dried, and as a result A small amount of undissolved material remained. In addition, although the sample of the target example 1 is a commercially available laminate type ink jet recording paper, a large amount of the laminar remains on the screen as undissolved material.

  The ink jet recording paper of the present invention can be used as an ink jet recording paper having a glossy photo recording among the ink jet recording papers.

Claims (6)

  In an ink jet recording paper in which an ink receiving layer is provided on a support having a base paper coated with a resin coating layer, the support uses an aqueous polymer dispersion having a minimum film forming temperature of 30 to 100 ° C. and a white pigment as essential components. The aqueous polymer dispersion is obtained by coating the resin coating layer composed of a resin composition containing 10 to 35 parts by weight of a white pigment with respect to 100 parts by weight of a dry solid content, The ink-receiving layer aqueous coating solution is applied without the hydrophilic coating treatment on the surface of the resin coating layer, and the waste paper of the ink jet recording paper (including damaged paper at the time of manufacture) has disintegration properties. Inkjet recording paper characterized by the above.   High molecular aqueous dispersion is polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyvinyl acetate, polystyrene, ethylene copolymer, acrylic copolymer, vinyl chloride copolymer, styrene / butadiene copolymer. The inkjet recording paper according to claim 1, which is at least one selected from the group consisting of a methacrylic acid / butadiene copolymer, an ethylene ionomer base resin, and a styrene ionomer base resin.   The ethylene ionomer base resin is an ethylene / acrylic acid copolymer, an ethylene / methacrylic acid copolymer, an ethylene / maleic acid copolymer, an ethylene / fumaric acid copolymer, or an ethylene / maleic anhydride copolymer. The inkjet recording paper according to claim 2.   The ink jet recording paper according to claim 3, wherein the ethylene ionomer base resin is an ethylene / acrylic acid copolymer or an ethylene / methacrylic acid copolymer.   The styrene ionomer base resin is a styrene / acrylic acid copolymer, a styrene / methacrylic acid copolymer, a styrene / maleic acid copolymer, a styrene / fumaric acid copolymer, or a styrene / maleic anhydride copolymer. The inkjet recording paper according to claim 2.   White pigment is calcium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium oxide, zinc oxide, satin white, aluminum silicate, calcium silicate, magnesium silicate, synthetic silica, aluminum hydroxide, alumina, styrene resin, The ink jet recording paper according to claim 1, wherein the ink jet recording paper is at least one selected from the group consisting of an acrylic resin, polyethylene, urea resin, and melamine resin.