JP6344249B2 - Ink jet recording paper and method for manufacturing ink jet recording paper - Google Patents

Description

  The present invention relates to an inkjet recording paper and a method for manufacturing an inkjet recording paper. Specifically, the present invention relates to an inkjet recording paper that can perform good printing using inkjet printing even when the basis weight is low.

  Ink-jet printing for printing using the ink-jet method is not limited to photo printing, terminal PC (personal computer) printers, fax machines, or copiers. Ink-jet printing is being put to practical use in the field of so-called on-demand printing because it enables multi-product small-lot printing and variable information printing. Inkjet printing is rapidly penetrating in the printing field where the number of prints per printing lot is small because there is no need for plate production. In the ink jet method, printing speed has been increased and image quality has been improved, and application to offset printing, gravure printing, publication printing, newspaper printing, notebook printing, and inkjet commercial printing is being studied.

  In the ink jet method, ink droplets are ejected onto the surface of the printing paper by various methods to form images and characters on the surface of the printing paper. Such an ink jet method has advantages that it is easy to achieve high speed and full color, and has low noise during output. Moreover, since the apparatus used for an inkjet system is low-cost, it is utilized in many fields.

  In inkjet commercial printing, printing is performed continuously. In such an inkjet commercial printing market, the printing speed is further increased. Ink jet commercial printing machines have appeared that have a printing paper transport speed of 200 m / min or higher, and more than 300 m / min at higher speeds.

Printing paper used when printing on an inkjet commercial printing machine is required to have high ink absorbability. In particular, when printing photographic images and designs, the amount of ink ejected onto the printing paper increases, and higher ink absorbency is required. If the ink absorbability of the printing paper is insufficient, ink absorption unevenness occurs, or blurring occurs on the boundary lines of different colors of the printed matter, resulting in a decrease in print quality. Further, during the printing operation, the paper feeding paper roll is soiled with ink, and the ink adhering to the paper feeding paper roll is retransferred to the paper, so that the printing speed cannot be increased. Furthermore, if it becomes difficult to fix the ink on the printing paper due to low absorption, the ink may fall off when it is wound up after printing, or the ink may fall off from the printed matter when the surface of the printing paper is rubbed after printing. Occurs.
For example, when printing on a conventional notebook paper as described in Patent Document 1 using an ink jet printer, there is no absorbability of water-based ink-jet ink. It is generated, and the current notebook print quality is not obtained.

  In order to solve this situation, various studies have been conducted so far as shown below. For example, Patent Document 2 describes newsprint paper that can be inkjet printed. Here, the disintegrated pulp type and fiber length used are optimized, and the water absorption time and the shape factor by ink jet printing are defined. In Patent Document 3, it is proposed to arrange a polyvalent salt on the surface of newspaper paper for ink jet printing. Patent Document 4 describes that an alkylamine / ammonia / epihalohydrin polycondensate is used for a sheet used in a high-speed rotary inkjet system, and that an optimum cobb size is specified. Patent Document 5 discloses an ink jet recording paper having a recording layer containing a polyamine epichlorohydrin copolymer.

In general, when the basis weight of ink jet recording paper is low, ink printed on the front surface of the paper permeates the inside of the paper and the ink penetrates to the back surface. For this reason, in ordinary ink jet recording paper, the basis weight is often about 82 g / m ^{2, and at least} about 64 to 70 g / m ² . For example, in Patent Document 4, a support having a basis weight of 80 g / m ² is used. In Patent Document 5, an inkjet recording paper having a basis weight of 64 g / m ² or more is preferred.

On the other hand, papers used for notebooks, papers constituting dictionaries, newsprint papers, and the like are required to have a low basis weight so as not to be bulky when binding. For example, Patent Documents 2 and 3 disclose newspapers that can be inkjet-printed, and Patent Document 2 discloses newspapers having a basis weight of 43 g / m ² . In general, notebook paper is required to have a basis weight of about 60 g / m ² .

JP 2000-328495 A JP 2011-161720 A JP 2010-516524 A JP 2000-247016 A JP 2013-226834 A

However, when ink jet printing is performed on newspapers as disclosed in Patent Documents 2 and 3, the ink jet aptitude is not sufficient, and it is clear from the study by the present inventors that ink breakthrough occurs. It was. Moreover, when the basic weight of the inkjet recording paper as disclosed in Patent Documents 4 and 5 is changed to about 60 g / m ² and inkjet printing is performed, there is a problem that sufficient inkjet aptitude is not exhibited. That is, the ink jet aptitude is not sufficiently obtained in the ink jet recording paper whose basis weight is suppressed to a certain value or less, and further improvement has been demanded.

  In order to improve the ink jet suitability of the ink jet recording paper, a method of adding a large amount of internally added pigment can be considered. However, when a large amount of the internally added pigment is added, there arises a problem that the slipperiness of the paper is lowered and the printing speed cannot be increased. Further, since the paper strength of the ink jet recording paper is reduced, there is a problem that paper breakage occurs during printing or when the paper is used.

  Therefore, in order to solve the problems of the prior art, the present inventors have studied for the purpose of providing an inkjet recording paper having a low basis weight and having both inkjet suitability and paper strength. Advanced.

As a result of repeated researches to solve the various problems described above, the present inventors have obtained a layer containing substantially no pigment, a layer containing a polyamine epichlorohydrin copolymer having a specific molecular weight, and a base paper. Ink jet recording paper including ink jet aptitude and paper even when the basis weight is reduced by containing a neutral sizing agent in the base paper and containing 12 to 30% by mass of calcium carbonate in the base paper. It has been found that an ink jet recording paper having strength can be obtained.
Specifically, the present invention has the following configuration.

[1] An inkjet recording paper comprising a base paper and a layer containing a polyamine epichlorohydrin copolymer disposed on at least one side of the base paper, wherein the content of the pigment in the layer is 1 with respect to the total mass of the layer The weight average molecular weight of the polyamine epichlorohydrin copolymer is 500 to 3000, the base paper contains a neutral sizing agent and calcium carbonate, and the content of calcium carbonate is the solid content of pulp in the base paper Inkjet recording paper, wherein the basis weight of the inkjet recording paper is 17 to 63 g / m ² with respect to the total mass.
[2] The inkjet recording paper according to [1], wherein the neutral sizing agent is at least one selected from alkenyl succinic anhydride and alkyl ketene dimer.
[3] The ink jet recording paper according to [1] or [2], wherein the base paper contains 0.1 to 0.6 parts by mass of a neutral sizing agent with respect to 100 parts by mass of pulp solid content.
[4] The ink jet recording paper according to any one of [1] to [3], wherein the base paper contains 0.1 to 0.6 parts by mass of alkenyl succinic anhydride with respect to 100 parts by mass of pulp solid content.
[5] The inkjet recording paper according to any one of [1] to [4], wherein the content of the polyamine epichlorohydrin copolymer in the layer is 30 to 60% by mass with respect to the total mass of the layer.
[6] The inkjet recording paper according to any one of [1] to [5], which is used as a notebook paper.
[7] A method for producing an inkjet recording paper, comprising: a step of applying a surface treatment liquid to a base paper; and a step of drying the surface treatment liquid, wherein the surface treatment liquid has a weight average molecular weight of 500 to 3,000 polyamine epichlorohydrin The content of the pigment in the surface treatment liquid is 1% by mass or less with respect to the total mass of the surface treatment liquid, and the base paper contains a neutral sizing agent and calcium carbonate, and contains calcium carbonate. The amount is 12 to 30% by mass with respect to the total mass of the pulp solid content in the base paper, and the basis weight of the inkjet recording paper is 17 to 63 g / m ^2. Method.
[8] The method for producing an inkjet recording paper according to [7], wherein in the step of applying the surface treatment liquid, the coating amount of the surface treatment liquid is 0.1 to 5.0 g / m ² in terms of solid content per side.
[9] The method for producing an inkjet recording paper according to [7] or [8], wherein the content of the polyamine epichlorohydrin copolymer in the surface treatment liquid is 30 to 60% by mass with respect to the total solid content mass.

  According to the present invention, both ink jet aptitude and paper strength can be improved even with an ink jet recording paper having a low basis weight. By using such an inkjet recording paper, it is possible to obtain a high-quality printed material that is excellent in handleability.

  Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

(Inkjet recording paper)
The present invention relates to an ink jet recording paper comprising a base paper and a layer containing a polyamine epichlorohydrin copolymer disposed on at least one side of the base paper. The basis weight of the inkjet recording paper of the present invention is 17 to 63 g / m ² . Here, the content of the pigment in the layer is 1% by mass or less based on the total mass of the layer, and the layer is substantially free of pigment. The weight average molecular weight of the polyamine epichlorohydrin copolymer contained in the layer is 500 to 3000. The base paper contains a neutral sizing agent and calcium carbonate, and the content of calcium carbonate is 12 to 30% by mass relative to the total mass of pulp solids in the base paper. The ink jet recording paper of the present invention is a paper for performing ink jet printing, and is a paper used for obtaining a high-quality printed matter.

  Since the ink jet recording paper of the present invention has the above-described configuration, it is an ink jet recording paper having a low basis weight, and both ink jet aptitude and paper strength are enhanced. The ink jet recording paper of the present invention has excellent handling properties because of its high paper strength, and even when the printing speed of ink jet printing is increased, there is little risk of paper breakage or the like. In addition, since the ink jet recording paper of the present invention is excellent in ink jet aptitude, a high-quality printed matter can be obtained. In the present specification, “excellent ink jet aptitude” means (1) evaluation of ink bleeding, (2) evaluation of ink drying property, (3) evaluation of ink penetration, and (4) after printing. High evaluation is obtained in any of the evaluation of water resistance of printing, (5) evaluation of scratch resistance of printing after printing, and (6) evaluation of printing unevenness.

The ink jet recording paper of the present invention can be preferably used for notebook paper, dictionary paper, manual paper, maintenance notebook paper for automobiles, and the like. Furthermore, it can also be preferably used for paper used when enclosing in an envelope and mailing. For example, it can be used for a credit card usage statement sheet, a bank usage statement sheet, a correspondence course material sheet, and the like. Thereby, increase of the amount of enclosure can be suppressed and transportation cost can be reduced.
Among these, the inkjet recording paper of the present invention is suitable as a notebook paper. The inkjet recording paper used for such applications has a low basis weight so as not to be bulky when bound. The basis weight of the ink jet recording sheet may be any 17~63g / m ^2, it is preferably 20 to 60 g / m ^2, and more preferably 25~55g / m ^2. By setting the basis weight of the inkjet recording paper within the above range, it is possible to suppress bulkiness and weight increase when used for various applications while increasing paper strength. Moreover, inkjet printing can be performed on both surfaces by making the basic weight of an inkjet recording paper into the said range.

  Conventionally, a large number of notebook papers are generally produced by offset printing or the like. However, in recent years, there is a growing tendency to produce and sell a wide variety of small lots due to diversification of individual preferences. In addition, notebooks distributed by companies tend to produce and sell many types of small lots due to the splitting of large companies, and we used a conventional large offset printing press that requires plates to be produced and replaced for each printing lot. The drop in productivity is great. For this reason, the inkjet recording paper whose basis weight was suppressed low, and the inkjet recording paper whose inkjet suitability was improved is preferably used for a notebook paper or the like.

  Since the inkjet recording paper of the present invention is positioned as a replacement product for offset printing paper that is currently widely used, it is preferable that the hue is close to that of offset printing notebook paper. Specifically, the whiteness is preferably about 82 ± 5%.

  The opacity of the ink jet recording paper of the present invention is not particularly limited, but if it is 75% or more, preferably 80% or more, the opacity after printing can be maintained without the printing surface being transparent on the back surface of the printing surface. The opacity is a value measured by a measuring method based on JIS P8149.

(Base paper)
The ink jet recording paper of the present invention includes a base paper as a support. The base paper is a paper mainly composed of pulp fibers or a sheet mainly composed of pulp fibers. Wood pulp can be used for the pulp fiber, and hardwood-derived pulp or softwood-derived pulp can be used. In addition, deinked pulp (such as DIP), chemical pulp (such as NBKP and LBKP), and mechanical pulp (such as GP, CGP, RGP, PGW, and TMP) can be used. Such pulp can be used alone or mixed at an arbitrary ratio.

  The freeness of the pulp used in the present invention is 300 to 500 ml C.I. S. F. It is preferable that By setting the freeness of the pulp within the above range, the drying load in the drying process can be reduced, and the papermaking speed can be increased. Moreover, the intensity | strength of an inkjet recording paper can be raised by making the freeness of a pulp into the said range.

  The base paper contains a neutral sizing agent. The neutral sizing agent used in the present invention is preferably at least one selected from alkenyl succinic anhydride and alkyl ketene dimer, and more preferably alkenyl succinic anhydride. By including such a neutral sizing agent in the base paper, it is possible to suppress the ink see-through of the ink jet recording paper.

  In the present invention, by using a neutral sizing agent, even when calcium carbonate is used, it is possible to suppress the occurrence of poor operation in the paper machine. By using a neutral sizing agent, precipitation of calcium carbonate can be suppressed, and adhesion of calcium carbonate to a paper machine or the like can be suppressed. Further, by using a neutral sizing agent, the ink absorbability can be increased.

The neutral sizing agent is preferably contained in an amount of 0.1 to 0.6 parts by mass, more preferably 0.2 to 0.4 parts by mass with respect to 100 parts by mass of the pulp solid content in the base paper. By setting the content of the neutral sizing agent within the above range, it is possible to suppress the ink from penetrating in the ink jet recording paper having a basis weight of 63 g / m ² or less, and to improve the ink absorbability. be able to.
Among them, the base paper preferably contains alkenyl succinic anhydride, and the content of alkenyl succinic anhydride is preferably in the above range. Alkenyl succinic anhydride is preferably used because it can suppress the slipperiness of the ink jet recording paper and suppress the paper feed failure during ink jet printing.

  The base paper contains calcium carbonate as an internal pigment. The content of calcium carbonate contained in the base paper may be 12 to 30% by mass with respect to the total mass of pulp solids in the base paper, and is preferably 15 to 30% by mass. By setting the content of calcium carbonate within the above range, sufficient paper strength can be obtained, and the occurrence of paper breakage can be suppressed when printing or when used as a notebook. Such an ink jet recording sheet is excellent in handleability. Further, by setting the content of calcium carbonate within the above range, it is possible to prevent the ink from penetrating in the ink jet recording paper, and to further increase the ink absorbability. Furthermore, by making the content of calcium carbonate within the above range, the slipperiness of the ink jet recording paper can be adjusted, and the occurrence of paper feeding troubles during ink jet printing can be prevented.

  The base paper preferably further contains a filler in addition to calcium carbonate. Examples of the filler include white carbon, clay, amorphous silica, talc, and titanium oxide. Calcium carbonate and filler are preferably added when making a base paper. The filler content is preferably 0 to 18% by mass with respect to the total mass of pulp solids in the base paper, and the total content of calcium carbonate and filler is preferably 30% by mass or less.

  In addition, known paper making chemicals such as a fixing agent, a paper strength enhancer, a yield improver, a water resistance agent, and an ultraviolet absorber may be appropriately added to the base paper as necessary. Various colorants may be used to approximate the hue of the offset printing notebook paper. These chemicals are also preferably added when making paper.

The basis weight of base paper is preferably 15~63g / m ^2, more preferably from 20 to 60 g / m ^2, further preferably 20~55g / m ^2. By setting the basis weight of the base paper within the above range, it is possible to suppress bulkiness and weight increase when used for various purposes while increasing paper strength. Moreover, inkjet printing can be performed on both surfaces by making the basic weight of a base paper into the said range.

  The base paper is made by a known method. As the paper machine, for example, a commercial paper machine such as a long net paper machine, a gap former type paper machine, a circular net paper machine, or a short net paper machine is appropriately selected according to the purpose.

(Layer containing polyamine epichlorohydrin copolymer)
A layer containing a polyamine epichlorohydrin copolymer is disposed on at least one side of the base paper. The content of the polyamine epichlorohydrin copolymer in this layer is preferably 30 to 60% by mass and more preferably 35 to 55% by mass with respect to the total mass of the layer. By setting the content of the polyamine epichlorohydrin copolymer within the above range, it is possible to suppress the back-through of the ink and to increase the absorbability of the ink.

  The polyamine epichlorohydrin copolymer is a copolymer (cationic resin) of amine and epichlorohydrin. As the polyamine epichlorohydrin copolymer, for example, DK6802 (weight average molecular weight 1000) manufactured by Starlight PMC, DK6810 (weight average molecular weight 20009) or the like can be used.

  The weight average molecular weight of the polyamine epichlorohydrin copolymer used in the present invention may be 500 to 3000, preferably 500 to 2500, and more preferably 800 to 2000. By setting the weight average molecular weight of the polyamine epichlorohydrin copolymer within the above range, the permeability and barrier property of the ink can be controlled within an appropriate range, and the occurrence of ink breakthrough can be suppressed. Printing with high image quality can be performed. Further, the ink absorbability can be increased by controlling the ink permeability and barrier property within an appropriate range.

The weight average molecular weight of the polyamine epichlorohydrin copolymer can be measured by gel permeation chromatography. The measurement conditions are as follows.
Solvent: water distilled water column: OHpak SB-806M HQ Shodex was used by connecting two)
Column temperature: 40 ° C
Sample concentration: 0.1% by mass
Detector: 1200 series detector (Agilate Technology)
Pump: 1200 series detector (Agilate Technology)
Flow rate: 0.5 ml / min
Calibration curve: Shodex Standard P-82 (Pullulan) (manufactured by Shodex) Mw = 1000 to 20,000 calibration curves were used.

  The layer containing the polyamine epichlorohydrin copolymer is preferably a layer that does not substantially contain a pigment. “Substantially free of pigment” specifically means that the pigment content is 1% by mass or less based on the total mass of the layer. By making the layer containing the polyamine epichlorohydrin copolymer a layer that does not substantially contain a pigment, the ink absorbability can be enhanced.

  In addition to the polyamine epichlorohydrin copolymer, a metal salt such as other cationic resin or aluminum sulfate may be blended in the layer containing the polyamine epichlorohydrin copolymer.

Examples of other cationic resins include (1) alkylamine-epichlorohydrin copolymers, (2) acrylic polymers having secondary amino groups, tertiary amino groups and quaternary ammonium groups, and (3) polyvinyl. Amines, polyvinylamidines, 5-membered cyclic amidines, (4) dicyandication resins typified by dicyandiamide-formalin copolymers, (5) polyamine cation resins typified by dicyandiamide-polyethyleneamine copolymers, (6 ) polyalkylene polyamines or derivatives thereof, such as polyethylene polyamine or polypropylene polyamine, (7) diallyldimethylammonium -SO ₂ copolymer, (8) diallylamine salt -SO ₂ copolymer, (9) diallyl dimethyl ammonium chloride polymers (10) allylamine salt polymer, (11) Homopolymer or copolymer of vinylbenzyltriallylammonium salt, (12) Dialkylaminoethyl (meth) acrylate quaternary salt copolymer, (13) Acrylamide-diallylamine salt copolymer, (14) Poly Examples of the commercially available products include aluminum salts such as aluminum chloride and polyaluminum acetate. Examples of metal salts other than aluminum sulfate include magnesium sulfate, zinc sulfate, calcium formate, calcium acetate, and calcium nitrate.

  The layer containing the polyamine epichlorohydrin copolymer may contain starch as a binder. Examples of the starch include alkyl-modified starch, cationized starch, raw starch, oxidized starch, etherified starch, and esterified starch. These starches have good compatibility with the later-described solution-type styrene polymer and solution-type styrene-acrylic copolymer, and the solution-type styrene-acrylic copolymer is added to the layer containing the polyamine epichlorohydrin copolymer. It can be distributed uniformly. In addition, said binder can also be mix | blended with a base paper.

  The starch content is preferably 40 to 90 mass%, more preferably 50 to 80 mass%, based on the total mass of the layer. By setting the content of starches within the above range, it is possible to suppress a decrease in surface strength, and it is possible to prevent the occurrence of rubbing stains on the printed portion. In addition, it is possible to improve the drying property of the ink during printing, and it is possible to suppress the occurrence of unevenness in printing.

  In addition to starches, water-soluble celluloses such as carboxymethyl cellulose, methyl cellulose, and hydroxyalkyl cellulose as binders, natural water-soluble polymer derivatives such as alginic acid, guar gum, xanthan gum, pullulan, cationized polyvinyl alcohol, polyvinyl alcohol, polyacrylamide Etc. may be used.

The layer containing a polyamine epichlorohydrin copolymer may contain a solution-type styrene polymer or a solution-type styrene-acrylic copolymer as a surface sizing agent. The content of the surface sizing agent is preferably 0.1 to 4% by mass and more preferably 0.2 to 3% by mass with respect to the total mass of the layer. By setting the content of the surface sizing agent within the above range, ink jet printing suitability can be enhanced. Specifically, the occurrence of bleeding or the like during printing can be suppressed, and the drying property of the ink can be improved.
In addition, as a solution-type styrene-type polymer or a solution-type styrene-acrylic-type copolymer, SS2700 by Seiko PMC etc. can be mentioned as a commercial item.

  The layer containing the polyamine epichlorohydrin copolymer may contain a colorant. Examples of the colorant to be used include azo compounds (dithizone, formazan), quinone series (naphthoquinone, anthraquinone, acridone, anthanthrone, indanthrene, pyrendione, violanthrone), quinoneimine (azine, oxazine, thiazine), indigo dye ( Indirubin, oxyindigo, thioindigo), sulfur dyes, diphenylmethane, triphenylmethane (fluorane, fluorescein, rhodamine), ferrocene, fluorenone, fulgide, perylene, phenazine, phenothiazine, polylene (carotene, maleic acid derivative, pyrrolazine, stilbene, styryl) , Polymethine (cyanine, pyridinium, pyrylium, quinolinium, rhodanine), xanthene, alizarin, acridine, acridinone, carbos Ryl, coumarin, diphenylamine, phthaloperinone, porphine, chlorophyll, phthalocyanine, crown compound, squarylium, thiafulvalene, thiazole, nitro dye, nitroso dye, dye-based colorant such as leuco dye after color development, titanium black, titanium yellow, ultramarine blue, Bituminous, cobalt blue, carbon black, iron black, zinc oxide, cobalt oxide, silicon oxide, aluminum hydroxide, azo pigment, phthalocyanine pigment, dyed lake, starch, urea-formalin resin, melamine resin and other synthetic resin particles, silicone particles And pigment dyes such as stilbene, distilbene, benzoxazole, coumarin, distilbene, benzimidazole and pyrazoline. These colorants may be used to approximate the hue of offset printing paper, and the colorants may be used alone or in combination.

  Moreover, various adjuvants may be mix | blended with the layer containing a polyamine epichlorohydrin copolymer as needed. As the auxiliary agent, for example, surfactant, pH adjuster, viscosity adjuster, softener, gloss imparting agent, waxes, dispersant, flow modifier, stabilizer, antistatic agent, cross-linking agent, sizing agent, Examples include ultraviolet absorbers, antifoaming agents, water resistance agents, plasticizers, lubricants, preservatives, and fragrances.

  The thickness of the layer containing the polyamine epichlorohydrin copolymer is preferably 10 to 40 μm. By setting the thickness of the layer containing the polyamine epichlorohydrin copolymer within the above range, it is possible to improve the ink penetration property. Moreover, by setting the thickness of the layer within the above range, a polyamine epichlorohydrin copolymer supplementing the colorant component can be present in the surface layer, and ink jet printing suitability can be enhanced. Moreover, the production cost of the inkjet recording paper can be suppressed.

(Inkjet recording paper manufacturing method)
The present invention also relates to a method for manufacturing the above-described inkjet recording paper. The method for producing an inkjet recording paper of the present invention includes a step of applying a surface treatment liquid to a base paper and a step of drying the surface treatment liquid. Here, the surface treatment liquid contains a polyamine epichlorohydrin copolymer having a weight average molecular weight of 500 to 3000, and the content of the pigment in the surface treatment liquid is 1% by mass or less based on the total mass of the surface treatment liquid. . The surface treatment liquid forms a layer containing the above-described polyamine epichlorohydrin copolymer after coating and drying. The base paper to which the surface treatment liquid is applied is a base paper having the above-described configuration, and the base paper includes a neutral sizing agent and calcium carbonate, and the content of calcium carbonate is based on the total mass of pulp solids in the base paper. And 12 to 30% by mass. In the production method of the present invention, an inkjet recording paper having a basis weight of 17 to 63 g / m ² is produced.

  The neutral sizing agent contained in the base paper used in the method for producing an inkjet recording paper is preferably at least one selected from alkenyl succinic anhydride and alkyl ketene dimer, and more preferably alkenyl succinic anhydride. The neutral sizing agent is preferably contained in an amount of 0.1 to 0.6 parts by mass and more preferably 0.2 to 0.4 parts by mass with respect to 100 parts by mass of the pulp solid content.

In the step of applying the surface treatment solution is preferably applied amount of the surface treatment liquid is 0.1 to 5.0 g / m ² in terms of solid per side content, is 0.5~4.5g / m ² More preferably, it is 1.0-3.0 g / m < ² >. By setting the coating amount after drying of the surface treatment liquid (in terms of solid content) within the above range, it is possible to suppress ink back-through and the like, and to improve ink jet printing suitability. Also, the drying property of the ink can be improved.

  The surface treatment liquid contains a polyamine epichlorohydrin copolymer. The content of the polyamine epichlorohydrin copolymer in the surface treatment liquid is preferably 30 to 60% by mass, and more preferably 35 to 55% by mass with respect to the total solid content. By setting the content of the polyamine epichlorohydrin copolymer within the above range, it is possible to suppress the back-through of the ink and to increase the absorbability of the ink.

  The surface treatment liquid may further contain a solution type styrene polymer or a solution type styrene-acrylic copolymer. The solution-type styrene polymer or the solution-type styrene-acrylic copolymer is contained in a state dissolved in the surface treatment liquid, and is uniformly applied when applied to the base paper. The solution-type styrene polymer or solution-type styrene-acrylic copolymer is a solution type and dissolves in water through a solvent, so that it is more soluble than a water dispersion type (so-called emulsion type). High nature. For this reason, the uniformity of the solid print portion is improved when applied to the base paper.

  The surface treatment liquid is substantially free of pigment. “Substantially free of pigment” specifically means that the pigment content is 1% by mass or less with respect to the total mass of the surface treatment liquid. By setting it as such conditions, the absorptivity of the ink of the inkjet recording paper manufactured can be improved.

  In addition, the surface treatment liquid may contain a layer containing a polyamine epichlorohydrin copolymer, other cationic resins other than the polyamine epichlorohydrin copolymer, metal salts such as aluminum sulfate, binders, colorants, and various auxiliary agents. May be blended.

  The apparatus for applying the surface treatment liquid to the base paper is not particularly limited. For example, a roll coater such as a 2 roll size press, a blade metalling size press, a rod metalling size press, a gate roll coater, a tray Use publicly known equipment such as ring, flexible, roll application, fountain application, short dwell and other bevel type and vent type blade coaters, rod blade coaters, bar coaters, air knife coaters, curtain coaters, spray coaters, gravure coaters, etc. be able to.

  In the step of drying the surface treatment liquid, various methods such as steam drying, gas heater drying, electric heater drying, infrared heater drying and the like can be employed.

  In the production of the ink jet recording paper of the present invention, a smoothing treatment may be performed with various calendar devices after the surface treatment liquid is applied and dried. As such a calender device, a commonly used calender device such as a super calender, a soft calender, a gloss calender, a compact calender, a mat super calender, or a mat calender can be appropriately used. As the calender finishing conditions, the temperature of the rigid roll, the calender pressure, the number of nips, the roll speed, the paper moisture before the calender, and the like are appropriately selected according to the required quality. Furthermore, the calendar device includes an off type that is different from the paper machine and an on type that is integrated with the paper machine, and can be used in either case. As the material of the calendar device to be used, when a rigid roll is used, a metal or a roll whose surface is mirror-finished with hard chrome plating or the like can be employed. When using an elastic roll, a roll formed by molding a resin roll such as a urethane resin, an epoxy resin, a polyamide resin, a phenol resin, or a polyacrylate resin, cotton, nylon, asbestos, an aramid fiber, or the like can be used. In addition, after finishing with a calendar, it is also possible to use an appropriate combination of a water coating device, an electrostatic humidifier, a steam humidifier, and the like for controlling and humidifying the inkjet recording paper.

(Printed matter)
The inkjet recording paper of the present invention is subjected to inkjet printing. In inkjet printing, an image or a character is formed by depositing ink on a layer containing a polyamine epichlorohydrin copolymer. The present invention may relate to an inkjet recording paper (printed material) on which inkjet printing has been performed. When the printed material is notebook paper, ruled lines, dates, and the like are printed on the inkjet recording paper. When the printed material is dictionary paper, characters and the like are printed. The ink used for inkjet printing preferably contains an aqueous dye / aqueous pigment.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

Example 1
<Preparation of substrate>
After mixing and disaggregating at a ratio of 60 parts by mass of deinked waste paper pulp, 20 parts by mass of thermomechanical pulp, 10 parts by mass of grind pulp, and 10 parts by mass of softwood kraft pulp, 400 ml C.I. S. F. It was. 1 part by mass of sulfuric acid band, 100 parts by mass of this pulp, 1 part by mass of cationized starch (Ace K-100 manufactured by Oji Cornstarch), and alkenyl succinic anhydride (size pine SA-864 manufactured by Arakawa Chemical Industries) as an internal sizing agent 0.3 parts by weight was added. Thereafter, 20 parts by mass of calcium carbonate as a filler was mixed, and 0.011 part by mass of a yield agent (Keiwa Sangyo Keith Lock RP40L, polyacrylamide) was further added. The paper stock prepared in this way was made with a long mesh multi-cylinder paper machine to obtain a base paper having a basis weight of 50 g / m ² .

On the above base paper, 59 parts by mass of oxidized starch (manufactured by Oji Cornstarch, Ace A), 1 part by mass of a surface sizing agent (Seiko PMC, SE2220), polyamine epichlorohydrin copolymer (DK6802 made by Seiko PMC, weight average) Molecular weight 1000) A surface treatment liquid containing a mixture in a proportion of 40 parts by mass was applied and dried with a two-roll size press so that the dry coating amount was 2.5 g / m ^{2 on} both sides, and the basis weight was 52.5 g. An inkjet recording paper for a notebook of / m ² was obtained.

(Example 2)
Example 1 except that the polyamine epichlorohydrin copolymer (DK6802 made by Starlight PMC, weight average molecular weight 1000) in the surface treatment liquid of Example 1 was changed to a polyamine epichlorohydrin copolymer (DK6810 made by Starlight PMC, weight average molecular weight 2000). A notebook inkjet recording paper was obtained in the same manner.

(Example 3)
An inkjet recording paper for notebooks was obtained in the same manner as in Example 1 except that the coating amount of the surface treatment liquid in Example 1 was changed from 2.5 g / m ² to 0.5 g / m ² .

Example 4
Ink-jet recording paper for notebooks was obtained in the same manner as in Example 1 except that the coating amount of the surface treatment liquid in Example 1 was changed from 2.5 g / m ² to 4.5 g / m ² .

(Example 5)
The same as in Example 1 except that 59 parts by mass of oxidized starch and 40 parts by mass of polyamine epichlorohydrin copolymer in the surface treatment liquid of Example 1 were changed to 79 parts by mass of oxidized starch and 20 parts by mass of polyamine epichlorohydrin copolymer, respectively. Thus, an inkjet recording paper for a notebook was obtained.

(Example 6)
Except that 59 parts by mass of oxidized starch and 40 parts by mass of polyamine epichlorohydrin copolymer in the surface treatment solution of Example 1 were changed to 19 parts by mass of oxidized starch and 80 parts by mass of polyamine epichlorohydrin copolymer, the same procedure as in Example 1 was carried out. An inkjet recording paper for notebooks was obtained.

(Example 7)
An inkjet recording paper for notebooks was obtained in the same manner as in Example 1 except that 20 parts by mass of calcium carbonate as a filler in the base paper of Example 1 was changed to 15 parts by mass.

(Example 8)
An inkjet recording paper for notebooks was obtained in the same manner as in Example 1 except that 20 parts by mass of calcium carbonate as a filler in the base paper of Example 1 was changed to 25 parts by mass.

Example 9
An inkjet recording paper for notebooks was obtained in the same manner as in Example 1 except that the amount of the internally added sizing agent in the base paper of Example 1 was changed from 0.3 parts by mass to 0.2 parts by mass.

(Example 10)
An inkjet recording paper for notebooks was obtained in the same manner as in Example 1 except that the amount of the internally added sizing agent in the base paper of Example 1 was changed from 0.3 parts by mass to 0.4 parts by mass.

(Example 11)
The sizing agent in the base paper of Example 1 was changed from 0.3 part by mass of alkenyl succinic anhydride (size pine SA-864, manufactured by Arakawa Chemical Industries) to 0.3 part by mass of alkyl ketene dimer (size pine K-287, manufactured by Arakawa Chemical Industries). An inkjet recording paper for notebooks was obtained in the same manner as in Example 1 except that the above was changed.

(Example 12)
An inkjet recording paper for notebooks was obtained in the same manner as in Example 1 except that the base paper having a basis weight of 50 g / m ² in Example 1 was changed to a base paper having a basis weight of 20 g / m ² .

(Example 13)
An inkjet recording paper for notebooks was obtained in the same manner as in Example 1 except that the base paper having a basis weight of 50 g / m ² in Example 1 was changed to a base paper having a basis weight of 60 g / m ² .

(Comparative Example 1)
An inkjet recording paper for notebooks was obtained in the same manner as in Example 1 except that 20 parts by mass of calcium carbonate as a filler in the base paper of Example 1 was changed to 5 parts by mass.

(Comparative Example 2)
An inkjet recording paper for notebooks was obtained in the same manner as in Example 1 except that 20 parts by mass of calcium carbonate as a filler in the base paper of Example 1 was changed to 40 parts by mass.
In addition, when ink jet printing was performed on this ink jet recording paper for notebook or when it was used as a notebook after printing, paper tearing occurred and it was not suitable as a notebook paper.

(Comparative Example 3)
Example except that the polyamine epichlorohydrin copolymer (DK6802 made by Starlight PMC, weight average molecular weight 1000) in the surface treatment solution of Example 1 was changed to a polyamine epichlorohydrin copolymer (DK6857 made by Starlight PMC, weight average molecular weight 10,000). In the same manner as in No. 1, an inkjet recording paper for notebooks was obtained.

(Comparative Example 4)
40 parts by mass of a polyamine epichlorohydrin copolymer (DK6805 made by Starlight PMC, weight average molecular weight 1000) in the surface treatment liquid of Example 1 was added to 40 parts by mass of polydiallyldimethylammonium chloride (Senka Unisense CP-91, weight average molecular weight 20000). An ink jet recording paper for notebook was obtained in the same manner as in Example 1 except that the part was changed.

(Comparative Example 5)
40 parts by mass of a polyamine epichlorohydrin copolymer (DK6802 manufactured by Starlight PMC, weight average molecular weight 1000) in the surface treatment liquid of Example 1 was added to a dimethylamine / epichlorohydrin polycondensate (Satota Chemical Co., Ltd. Jetfix 36N, weight average molecular weight 3100). ) An inkjet recording paper for notebooks was obtained in the same manner as in Example 1 except that the amount was changed to 40 parts by mass.

(Comparative Example 6)
<Preparation of substrate>
After mixing and disaggregating at a ratio of 60 parts by mass of deinked waste paper pulp, 20 parts by mass of thermomechanical pulp, 10 parts by mass of grind pulp, and 10 parts by mass of softwood kraft pulp, 400 ml C.I. S. F. It was. For 100 parts by mass of this pulp, 0.01 parts by mass of alkyl ketene dimer as a sizing agent, 0.5 parts by mass of cationized starch (Ace K-100 manufactured by Oji Cornstarch), and 5 parts by mass of calcium carbonate as a filler Mixed. Thereafter, 0.01 part by mass of a yield agent (Keiwa Sangyo Keith Lock RP40L, polyacrylamide) was added. The paper stock prepared in this way was made with a long mesh multi-cylinder paper machine to obtain a base paper having a basis weight of 50 g / m ² .
On the above base paper, a coating solution containing only oxidized starch (manufactured by Oji Cornstarch, Ace A) was applied with a two-roll size press so that the both sides were 1 g / m ^2, and dried, and the basis weight was 51 g / m ² . Inkjet recording paper for notebooks was obtained.

(Comparative Example 7)
<Preparation of substrate>
After mixing and disaggregating at a ratio of 60 parts by mass of deinked pulp, 20 parts by mass of thermomechanical pulp, 10 parts by mass of grind pulp, and 10 parts by mass of softwood kraft pulp, 400 ml C.I. S. F. It was. 1 part by mass of a sulfuric acid band and 1 part by mass of cationized starch (Ace K-100 manufactured by Oji Corn Starch) were added to 100 parts by mass of this pulp. Then, 20 mass parts of calcium carbonate was mixed as a filler, and 0.011 mass part of a retention agent (Kyowa Sangyo Keith Lock RP40L, polyacrylamide) was further added. The paper stock prepared in this way was made with a long-net multi-tower paper machine to obtain a base paper having a basis weight of 50 g / m ² .

On the above base paper, 59 parts by mass of oxidized starch (manufactured by Oji Cornstarch, Ace A), 1 part by mass of a surface sizing agent (Seiko PMC, SE2220), polyamine epichlorohydrin copolymer (DK6802 made by Seiko PMC, weight average) Molecular weight 1000) A surface treatment liquid containing a mixture in a proportion of 40 parts by mass was applied and dried with a two-roll size press so that the dry coating amount was 2.5 g / m ^{2 on} both sides, and the basis weight was 52.5 g / An ink-jet recording paper for notebook of m ² was obtained.

(Comparative Example 8)
<Preparation of substrate>
Dissolve 100 parts by weight of broad-leaved kraft pulp and remove 400 ml C.I. S. F. It was. After adding 100 parts by mass of this pulp, 1 part by mass of sulfate band, 0.4 parts by mass of cationized starch (Ace K-100 manufactured by Oji Cornstarch), and 0.2 parts by mass of rosin emulsion as an internal sizing agent, a filler The paper stock prepared by mixing 5 parts by mass of talc was paper-made with a long mesh multi-cylinder paper machine to obtain a base paper having a basis weight of 50 g / m ² .

On the base paper, 20 parts by mass of oxidized starch (manufactured by Oji Cornstarch, Ace A), 5 parts by mass of polyvinyl alcohol (PVA-117, manufactured by Kuraray Co., Ltd.), 0.3 parts by mass of a surface sizing agent (Seiko PMC, SE2220), Polyamine epichlorohydrin copolymer (DK6802, manufactured by Starlight PMC, weight average molecular weight 1000) 2 rolls of a surface treatment solution containing a mixture of 74.7 parts by mass so that the dry coating amount is 1.5 g / m ^{2 on} both sides After applying with a size press machine and drying, an inkjet recording paper for notebook having a basis weight of 51.5 g / m ² was obtained.

(Evaluation)
The ink jet recording paper obtained in each example and comparative example was evaluated by the following method. The obtained results are shown in Table 1.

<Inkjet printing suitability / Barcode printing suitability (bleeding evaluation)>
After the “UCC / EAN128 code” is printed on Miyakoshi's high-speed inkjet printing system MJP600 on the inkjet recording paper obtained in each of the examples and comparative examples, the barcode verification machine “Inspector D4000” is printed on the inkjet printed EAN128 barcode. The barcode was scanned 10 times using (made by RJS) and evaluated.
(Evaluation criteria)
5: Reads 10 times out of 10 scans of the barcode reader.
4: Reads 9 times out of 10 scans of the barcode reader.
3: 6 or more and less than 9 out of 10 scans of the barcode reader.
2: Level that can be read by passing a plurality of scanning lines through the barcode.
1: Level that cannot be read.
In addition, when the evaluation is 3 or more, there is no practical problem.

<Inkjet printing suitability / ink drying property>
The ink-jet recording paper obtained in each Example and Comparative Example was printed with Miyakoshi's high-speed ink-jet printing system MJP600, and Gothic 8-point numbers from 1 to 10 were printed. A visual judgment was made on the dirt.
(Evaluation criteria)
5: There is no transfer stain and there is no influence on the discrimination of numbers.
4: There is slight transfer stain, but there is no effect on the discrimination of numbers.
3: There is transfer stain, but all numbers can be distinguished.
2: There is transfer stain, and some numbers such as 4, 6, 8, 9, 0 cannot be distinguished.
1: There is transfer stain, and all numbers cannot be identified.
Those having an evaluation of 3 or higher have high printing drying properties, and have no practical problem.

<Inkjet printing suitability / back-through>
Inkjet recording paper obtained in each of the examples and comparative examples was printed with Miyakoshi high-speed inkjet printing system MJP600, and “UCC / EAN128 code” was printed. Eight-point numbers on the body were ink-jet printed and visually judged for the effect of ink set-off.
(Evaluation criteria)
5: “UCC / EAN128 code” There is no set-off of the printed part, and there is no influence on the discrimination of numbers.
4: The “UCC / EAN128 code” print section is slightly offset, but it does not affect the discrimination of numbers.
3: The “UCC / EAN128 code” print section is offset, but all numbers can be identified.
2: The “UCC / EAN128 code” print section is flipped, and some numbers such as 4, 6, 8, 9, 10 cannot be identified.
1: The “UCC / EAN128 code” print section is offset, and all numbers cannot be identified.
In addition, the evaluation of 3 or more has no practical problem.

<Inkjet printing suitability / water resistance>
The inkjet recording paper obtained in each of the examples and comparative examples was printed with Miyakoshi's high-speed inkjet printing system MJP600, and Gothic 8-point numbers from 1 to 10 were printed, and then the inkjet-printed paper was placed in tap water for 30 seconds. After soaking, it was air dried. Thereafter, the degree of bleeding of the printed portion was visually evaluated.
(Evaluation criteria)
5: There is no bleeding of the printed part, and there is no influence on the discrimination of numbers.
4: Although there is a slight blur in the printed part, it does not affect the discrimination of numbers.
3: There is bleeding in the printed part, but all numbers can be distinguished.
2: There is bleeding in the printed part, and some numbers such as 4, 6, 8, 9, 10 cannot be identified.
1: There is bleeding in the printed part, and all numbers cannot be identified.
In addition, the evaluation of 3 or more has no practical problem.

<Inkjet printing suitability / abrasion resistance>
The inkjet recording paper obtained in each of the examples and comparative examples was printed with Miyakoshi high-speed inkjet printing system MJP600, and Gothic 8-point numbers from 1 to 10 were printed, and then the inkjet printing part was rubbed 10 times with waste. The degree of partial cosmetic stain was visually evaluated.
(Evaluation criteria)
5: There is no cosmetic stain, and there is no effect on the discrimination of numbers.
4: There is a slight amount of cosmetic stain, but there is no effect on the number discrimination.
3: Although there is a cosmetic stain, all numbers can be distinguished.
2: There is a cosmetic stain, and some numbers such as 4, 6, 8, 9, 10 cannot be identified.
1: There is a cosmetic stain, and all numbers cannot be identified.
In addition, the evaluation of 3 or more has no practical problem.

<Inkjet printing suitability / Solid print part uniformity>
After printing “Color Digital Standard Image Data / N3” published by the Japanese Standards Association with Miyakoshi high-speed inkjet printing system MJP600, the inkjet recording paper obtained in each example and comparative example is then printed in black, cyan, magenta, and yellow solid. The degree of printing unevenness of all the parts was visually evaluated.
(Evaluation criteria)
5: There is no printing unevenness and the image data is not affected.
4: Although there is slight printing unevenness, the image data is not affected.
3: There is printing unevenness, but the image is not damaged.
2: There is printing unevenness and the image is damaged.
1: There is intense printing unevenness.
Those having an evaluation of 2 or less have a problem in practical use.

<Handability>
After bundling 100 ink-jet recording papers obtained in each of the examples and comparative examples into A5 size, applying hot melt paste on the long sides of the laminated cross section, back-grinding and bookbinding, then 50 in order from the top Sheets of paper were turned by hand, and the state of paper tearing was visually evaluated.
(Evaluation criteria)
None (excellent): No paper breaks.
Existence (inferior): Paper breakage occurred on one or more sheets.
In addition, what exists has a problem in practical use.

Table 1 shows the evaluation results of ink jet printing suitability and handleability of Examples 1 to 13 and Comparative Examples 1 to 8.

  As is clear from the results in Table 1, the ink jet recording papers of Examples 1 to 13 satisfy all the evaluation items for ink jet aptitude required for ink jet recording papers in a well-balanced manner, and also have strong paper strength and handleability. It turns out that it is excellent.

Claims (9)

An ink jet recording paper comprising a base paper and a layer containing a polyamine epichlorohydrin copolymer disposed on at least one side of the base paper,
The content of the pigment in the layer is 1% by mass or less based on the total mass of the layer,
The polyamine epichlorohydrin copolymer has a weight average molecular weight of 500 to 3000,
The base paper contains a neutral sizing agent and calcium carbonate,
Content of the said calcium carbonate is 12-30 mass% with respect to the total mass of the pulp solid content in a base paper,
The basis weight of the inkjet recording paper is 17 to 63 g / m ² .   The inkjet recording paper according to claim 1, wherein the neutral sizing agent is at least one selected from alkenyl succinic anhydride and alkyl ketene dimer.   The inkjet recording paper according to claim 1 or 2, wherein the base paper contains 0.1 to 0.6 parts by mass of a neutral sizing agent with respect to 100 parts by mass of pulp solid content.   The inkjet recording paper according to any one of claims 1 to 3, wherein the base paper contains 0.1 to 0.6 parts by mass of alkenyl succinic anhydride with respect to 100 parts by mass of pulp solid content.   5. The ink jet recording paper according to claim 1, wherein the content of the polyamine epichlorohydrin copolymer in the layer is 30 to 60% by mass with respect to the total mass of the layer.   The inkjet recording paper according to any one of claims 1 to 5, which is used as a notebook paper. A method for producing an inkjet recording paper, comprising:
Including a step of applying a surface treatment liquid to a base paper, and a step of drying the surface treatment liquid,
The surface treatment liquid contains a polyamine epichlorohydrin copolymer having a weight average molecular weight of 500 to 3000,
The content of the pigment in the surface treatment liquid is 1% by mass or less based on the total mass of the surface treatment liquid,
The base paper contains a neutral sizing agent and calcium carbonate,
Content of the said calcium carbonate is 12-30 mass% with respect to the total mass of the pulp solid content in a base paper,
The basis weight of the said inkjet recording paper is 17-63 g / m < ² >, The manufacturing method of the inkjet recording paper characterized by the above-mentioned. The method for producing an inkjet recording paper according to claim 7, wherein in the step of applying the surface treatment liquid, the amount of the surface treatment liquid applied is 0.1 to 5.0 g / m ² in terms of solid content per side.   The method for producing an inkjet recording paper according to claim 7 or 8, wherein a content of the polyamine epichlorohydrin copolymer in the surface treatment liquid is 30 to 60% by mass with respect to a total solid mass.