JP5663252B2 - Inkjet recording paper and recording system - Google Patents

Description

  The present invention relates to a recording sheet and a recording system for non-aqueous ink jet printing, and in particular, to a recording sheet that includes a combination of predetermined additives, has significantly improved back-through, and is lightweight.

  Conventionally, in the ink jet recording system, water-soluble dye inks in which various water-soluble dyes are dissolved in water are mainly used. The water-soluble dye ink is excellent in maintainability of the ink discharge head of the ink jet recording apparatus, and is excellent in color developability and resolution after printing. However, ink-jet recording using water-based ink has various problems that occur when the printed portion of the recording material absorbs water in the ink and expands. This occurs because hydrogen bonds between fibers that maintain the mechanical strength of the support are broken by water. The stretching not only adversely affects the conveyance of the recording material in the printer, but also deviates the accuracy of the relative positional relationship between the recording material and the print head, thereby reducing the dimensional accuracy of the image or causing unevenness. It causes an undesirable phenomenon such as occurrence.

  On the other hand, the non-aqueous ink in which the pigment is dispersed in the non-aqueous solvent does not cause the recording material to stretch, has high dimensional accuracy, and can perform ink jet recording without causing unevenness in the image. is there. Further, since there is no elongation of the recording material, it is easy to convey and suitable for very high speed ink jet recording as compared with ink jet recording using water-based ink.

  However, when non-aqueous ink is used, there is a problem called “back-through” in which the pigment penetrates into the paper together with the solvent and the image can be seen through from the back side of the paper. In addition, since the image becomes easier to see as the paper becomes lighter, “back-through” tends to be prominent. In order to solve the “through-through”, a predetermined resin is dispersed or dissolved in the non-aqueous ink, and the Bristow absorption of the non-aqueous solvent is increased so that the paper is absorbed quickly, and the pigment is left on the resin component and the surface. It has been proposed to prevent back-through (Patent Documents 1 and 2).

  In addition, a plain paper that contains rosetta-type light calcium carbonate and a high molecular compound and has a stethito size of 5 seconds or more has been proposed (Patent Document 3). The degree of squeecht size is tested with a predetermined aqueous solution (JIS P 8122), and the smaller the value, the richer the water absorption. Therefore, setting this to a predetermined value or more means limiting the water absorption, and conversely, the absorption of the non-aqueous solvent becomes rapid. Thus, all of the prior arts are methods of accelerating the absorption of the non-aqueous solvent and leaving the pigment on the surface.

JP 2003-127522 A JP 2003-127523 A JP 2005-193660 A

  However, as a result of investigations by the present inventors, it has been found that the above method does not sufficiently reduce the back-through depending on the kind of the pigment and the dispersant resin, and may be worsened. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a lightweight recording sheet that is reduced in show-through and has a different approach from the prior art document.

As a result of various studies by the present inventors, it was surprisingly found that the strikethrough can be further reduced by setting the steecht sizing degree to 4 seconds or less. That is, the present invention
An inkjet recording paper for recording using a non-aqueous ink containing at least a pigment, a solvent, and a pigment dispersant,
Inorganic particles, acrylic resin, starch, and at least one selected from the group consisting of alkyl ketene dimer, alkenyl succinic anhydride, and neutral rosin,
This is an ink jet recording paper having a Steecht size measured according to JIS P 8122 of 0.1 to 4 seconds.

The ink jet recording paper of the present invention (hereinafter sometimes referred to as “recording paper”) is lightweight with a basis weight of 55 g / m ² or less, and has little show-through even when the steecht size is small. The effect is remarkable when used in combination with an ink containing a pigment-dispersed resin having a binding part.

  The recording paper of the present invention is plain paper. Plain paper refers to paper that does not have a coating layer containing a pigment. For this reason, paper dust is less likely to be produced even in high-speed printing. Furthermore, weight reduction can reduce the load at the time of conveyance, and it is environmentally preferable.

  In the recording paper of the present invention, the inorganic particles include light calcium carbonate, spindle-shaped light calcium carbonate, Rosetta-type light calcium carbonate in which primary particles of the spindle-shaped light calcium carbonate are aggregated radially, heavy calcium carbonate, kaolin, talc. Clay, silica, white carbon, aluminum hydroxide, zeolite, and titanium dioxide can be used. Moreover, you may use an organic particle together as needed. In terms of production cost, operability, and high opacity, light calcium carbonate is preferably used, and light calcium carbonate in a spindle or needle shape is more preferably used. More preferably, light calcium carbonate having an oil absorption of 20 to 100 ml / g (castor oil) and / or a particle size of 0.1 to 10 μm measured by laser diffraction is used.

  The inorganic particles are contained in an amount such that the ash content defined in JIS P 8251 is 20 to 35% by mass, preferably 22 to 30% by mass, based on the mass of the recording paper. Paper with an ash content of less than the lower limit is likely to show through, and paper with an ash content exceeding the upper limit has a reduced strength and poor productivity.

  The recording paper of the present invention includes a combination of three predetermined additives. The first of the additives is at least one selected from the group consisting of alkyl ketene dimers, alkenyl succinic anhydrides, and neutral rosins, and among them, alkyl ketene dimers are preferable.

  The second additive is an acrylic resin. Examples of the acrylic resin include polyacrylamide, styrene / (meth) acrylic acid copolymer, (meth) acrylic acid / (meth) acrylic acid ester copolymer, etc., preferably anionic acrylic resin For example, anionic polyacrylamide and anionic styrene / (meth) acrylic acid copolymer are used. Examples of the anionic polyacrylamide include DQ-10 manufactured by Arakawa Chemical Industries, Polymer Set 500, ST500 manufactured by Hoshiko PMC, Harima Chemical Co., Ltd. Haricoat G-51, and the like. Anionic styrene / (meth) acrylic acid based copolymer Examples of the coalesced polymer include polymeron 1383 manufactured by Arakawa Chemical Industries.

  The third additive is starch. In Patent Documents 1 and 2 above, oxidized starch is attached to the paper surface (for example, Patent Document 1, Paragraph 0063), and thus it is considered that starch has an effect of reducing the strikethrough. However, contrary to expectation, there was less show-through when the amount was less. Examples of starch include oxidized starch, cationized starch, hydroxyethylated starch, and phosphate esterified starch, among which oxidized starch is preferred.

  The amount of each additive can be appropriately set within a range in which the degree of sizing of the recording paper of the present invention is achieved. Preferably, at least one selected from the group consisting of alkyl ketene dimers, alkenyl succinic anhydrides, and neutral rosins is 0.05 to 0.6% by mass, more preferably 0.1%, based on the mass of the recording paper. It is contained at 0.5% by mass. If the amount of the resin is less than the lower limit, papermaking becomes difficult, and if the amount exceeds the upper limit, it is difficult to set the Steecht sizing degree to 4 seconds or less.

  The acrylic resin is used in an amount of 0.05 to 0.5 mass%, more preferably 0.1 to 0.4 mass%, based on the mass of the recording paper. If the amount of the resin is less than the lower limit value, the recording paper is yellowed over time, and if it exceeds the upper limit value, it is difficult to obtain a desired showthrough suppression effect. The method for evaluating the yellowing will be described in detail in Examples.

  The starch is preferably contained in an amount of 0.1 to 1.5% by mass, more preferably 0.3 to 1.0% by mass, based on the mass of the recording paper. If the amount of starch is less than the lower limit, when the paper and the paper supply roller come into contact with each other during transportation, the pulp or filler may fall from the paper surface, float in the machine, adhere to the head nozzle surface, and cause ink ejection failure. . When the upper limit is exceeded, it is difficult to obtain a desired strikethrough suppression effect.

As the pulp used for the recording paper of the present invention, any of those conventionally used for papermaking can be used. For example, hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood bleached sulfite pulp (LBSP), soft pulp bleached sulfite pulp (NBSP) and other chemical pulp, and wood pulp such as ground pulp (GP) and thermomechanical pulp (TMP), and used paper pulp (DIP). Further, non-wood pulp such as cotton pulp, hemp, bagasse, kenaf, esparto, cocoon, trifoam, and husk can also be used. Preferably, the freeness of the pulp to be used is 60 to 70 ° as the freeness of the shopper ligurer. If it is less than 60 °, it is a thin material with a basis weight of 55 g / m ² or less, and the paper with the ash content in the above range may have insufficient strength, and if it exceeds 70 °, the drainage becomes worse, so papermaking is difficult. There is a case.

  In addition, the recording paper of the present invention includes other sizing agents, paper strength enhancers, antifoaming agents, pH adjusters, dyes and colored pigments for adjusting hue, visual effects, and the like within a range not impairing the effects of the present invention An internal additive for papermaking such as a fluorescent dye for improving whiteness can be blended.

  As the paper machine for making the recording paper of the present invention, known apparatuses such as a long net paper machine, a twin-wire paper machine, and a Yankee paper machine can be appropriately used. Among these, the twin wire paper machine is preferable because the difference between the front and back of the paper such as the distribution of inorganic particles is reduced because dehydration is performed from both the upper and lower directions of the raw slurry. In order to obtain the recording paper in the present invention, adjustments such as jet wire ratio, profile, press, calendar, etc. are made as the papermaking conditions, and the drying conditions also adjust the vapor pressure and the ventilation method in the paper machine dryer.

  The sizing method is not particularly limited. For example, the alkyl ketene dimer is blended with pulp as an internal additive to make paper, and the obtained base paper is coated with a coating solution containing the acrylic resin and starch. After coating or impregnating by a method or impregnation method, it can be performed by drying. The impregnation can be performed using an impregnation type size press apparatus, and the coating is performed by various known coating apparatuses such as a blade coater, a roll coater, an air knife coater, a bar coater, a curtain coater, a gravure coater, and a gate roll coater. Can be used. In particular, it is preferable to use a size press apparatus and a gate roll coater as an on-machine coater because production costs can be reduced.

  In the coating liquid, a water retention agent, a water resistance agent, a pH adjuster, an antifoaming agent, a lubricant, a preservative, a surfactant, a conductive agent and the like are generally used as long as the effects of the present invention are not impaired. You may mix | blend the additive used for.

  As a drying method, for example, a normal method using a steam heater, a gas heater, an infrared heater, an electric heater, a hot air heater, a microwave, a cylinder dryer, or the like can be performed. After drying, if necessary, finishing processes such as post-processing such as super calender and soft calender may be performed to impart smoothness, or other general paper processing means may be used. In addition, if necessary, one side can be subjected to adhesive processing, lamination processing, or the like, and a coating layer for imparting various functions such as transportability, antistatic property, and writing property can also be provided.

Recording paper obtained by thus is preferably a basis weight as measured according to JIS P 8124 is a 55 g / ^{m 2} or less, more preferably 40~52g / ^{m 2.} The recording paper is generally paper having a basis weight of 60 g to 80 g / m ² , and can sufficiently meet the need for weight reduction.

Furthermore, the recording paper of the present invention preferably has a density measured according to JIS P 8118 of 0.60 to 0.80 g / cm ³ , more preferably 0.70 to 0.80 g / cm ^3. preferable. When the density is less than the lower limit, productivity tends to deteriorate, and when the density exceeds the upper limit, strike-through easily occurs. The density can be controlled by the linear pressure during the calendar process.

  Further, the recording paper of the present invention has a Steecht size measured in accordance with JIS P 8122 of 0.1 to 4 seconds, preferably 0.5 to 3 seconds. Paper with a Steecht sizing degree exceeding the upper limit is likely to show through, while a paper with a Steecht degree less than the lower limit has poor productivity. The degree of sizing can be achieved by adjusting the amount of each additive and papermaking conditions such as papermaking speed and dehydration method.

  Preferably, the recording paper has an ash content measured according to JIS P 8251 of 20 to 35% by mass, more preferably 20 to 30% by mass. The ash content is the amount of ash residue after the paper is burned at a temperature of 525 ± 25 ° C., expressed as a percentage of the absolute dry mass of the sample. The ash content can be achieved by adjusting the inorganic particle content and papermaking conditions.

  The recording paper of the present invention is used for ink jet recording using a non-aqueous ink (hereinafter sometimes referred to as “ink”) containing at least a pigment, a solvent, and a pigment dispersant. As the pigment used in the ink, any pigment generally used in the printing field can be used regardless of whether it is an inorganic pigment or an organic pigment. Specifically, for example, carbon black, cadmium red, molybdenum red, chrome yellow, cadmium yellow, titanium yellow, chromium oxide, pyridian, cobalt green, ultramarine blue, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment Conventionally known pigments such as quinacridone pigments, isoindolinone pigments, dioxazine pigments, selenium pigments, perylene pigments, perinone pigments, thioindigo pigments, quinophthalone pigments and metal complex pigments are not particularly limited. Can be used. These pigments may be used alone or in appropriate combination, but are desirably contained in the ink in the range of 0.01 to 20% by mass.

ここで、Ｒ^１は水素もしくは炭素数１〜３のアルキル基、好ましくはメチル基、Ｒ^２は炭素数６〜２５のアルキル基、Ｒ^３は炭素数６〜１６の２価の炭化水素基、Ｒ^４は炭素数２〜２０のアルキレン基もしくはオキシアルキレン基である。該アルキル（メタ）アクリレート共重合体は、インク中に０．１〜２０質量％で含まれることが好ましい。 The pigment dispersant is present in a dissolved or dispersed state in the ink, and improves the dispersibility of the pigment. The pigment dispersant is not particularly limited as long as the colorant to be used is stably dispersed in a solvent. For example, “Solsperse 5000 (copper phthalocyanine derivative), 11200, 13940 (polyesteramine type), 17000, 18000 (aliphatic amine type), 22000, 24000, 28000” (all trade names) manufactured by Nippon Lubrizol Corporation; Efka CHEMICALS “Fuka 400, 401, 402, 403, 450, 451, 453 (modified polyacrylate), 46, 47, 48, 49, 4010, 4050, 4055 (modified polyurethane)” (all trade names); manufactured by Kao “Demol P, EP”, “Poise 520, 521, 530”, “Homogenol L-18 (polycarboxylic acid type polymer surfactant)” (all trade names); “Disparon KS-860, manufactured by Enomoto Kasei Co., Ltd.” KS-873N4 (Amine salt of high molecular polyester ) "(All trade names);" Discall 202, 206, OA-202, OA-600 (multi-chain polymer nonionic system) "(all trade names) manufactured by Dai-ichi Kogyo Seiyaku; The urethanized oil described in Japanese Patent Application No. 2010-125785 and the alkyl (meth) acrylate copolymer described in Japanese Patent Application No. 2009-262702 by the applicant of the present application can be used. As the alkyl (meth) acrylate copolymer, those having 12 to 25 carbon atoms of the alkyl group and having a urethane bond part of 1 to 40% by mass of the copolymer are preferably used. The copolymer includes a main chain containing a repeating unit represented by the following formula (1) and a side chain or a crosslinked part (hereinafter referred to as “urethane bond”) containing a repeating unit represented by the following formula (2). Part)).

Here, R ¹ is hydrogen or an alkyl group having 1 to 3 carbon atoms, preferably a methyl group, R ² is an alkyl group having 6 to 25 carbon atoms, R ³ is a divalent hydrocarbon group having 6 to 16 carbon atoms, R ⁴ is an alkylene group or oxyalkylene group having 2 to 20 carbon atoms. The alkyl (meth) acrylate copolymer is preferably contained at 0.1 to 20% by mass in the ink.

  The alkyl (meth) acrylate copolymer can be obtained by the following method. In the first stage, a (meth) acrylate monomer having an alkyl group having 6 to 25 carbon atoms is radically polymerized according to a conventional method to obtain a polyalkyl (meth) acrylate main chain of the formula (1). Glycidyl (meth) acrylate is used. In the second step, the polyalkyl (meth) acrylate main chain having a glycidyl group obtained in the first step is reacted with the compound having a reactive group and an alcoholic hydroxyl group, and the formula A linking portion for bonding the urethane bond portion of (2) to the polyalkyl (meth) acrylate main chain is formed. As the compound having a glycidyl group, a reactive group, and an alcoholic hydroxyl group, amino alcohol, particularly diethanolamine is preferable.

  In the third stage, the polyalkyl (meth) acrylate main chain having an alcoholic hydroxyl group obtained in the second stage is reacted with a polyvalent isocyanate, and the remaining isocyanate group is reacted with a polyhydric alcohol to obtain a urethane. Construct a coupling part. The polyhydric alcohol may be added in the second stage. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, dipropylene glycol, 1,3 propanediol, polyethylene glycol, polypropylene glycol, and mixtures thereof. Examples of the polyvalent isocyanate compound include 1,6-diisocyanatohexane, 1,3-bis (isocyanatomethyl) benzene, 1,3-bis (isocyanatomethyl) cyclohexane, 1,5-naphthalene diisocyanate, And mixtures thereof. The reaction in the third stage can be performed by adding a polyvalent isocyanate compound or the like to the alkyl (meth) acrylate copolymer solution obtained in the second stage and heating in the presence of a tin catalyst or the like according to a conventional method. .

  The urethane bond part is contained in an amount of 1 to 40% by mass, preferably 1 to 30% by mass, and more preferably 5 to 20% by mass with respect to the mass of the alkyl (meth) acrylate copolymer. The mass of the urethane bond is the total mass of amino alcohol, polyhydric alcohol and polyvalent isocyanate compound used in the reaction.

  The alkyl (meth) acrylate copolymer has a mass average molecular weight of 5000 to 50,000, preferably 8000 to 30,000, as measured by GPC. If the molecular weight is less than the lower limit, the ink storage stability tends to deteriorate, and if the molecular weight exceeds the upper limit, the ink has a high viscosity and tends to deteriorate the inkjet discharge stability. is there.

  Examples of ink solvents include non-polar organic solvents such as aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, aromatic hydrocarbon solvents, and polar solvents such as ester solvents and alcohol solvents. . Examples of the aliphatic hydrocarbon solvent and alicyclic hydrocarbon solvent include, for example, “Teclean N-16, Teclean N-20, Teclean N-22, Nisseki Naphthezol L, Nissho Naphthezol M, manufactured by Nippon Petroleum Corporation. Nisseki Naphthezol H, No. 0 Solvent L, No. 0 Solvent M, No. 0 Solvent H, Nisseki Isosol 300, Nisseki Isosol 400, AF-4, AF-5, AF-6, AF-7 ", manufactured by Exxon “Isopar (Isopar) G, IsoparH, IsoparL, IsoparM, ExxsolD40, ExxsolD80, ExxsolD100, ExxsolD130, ExxsolD140” and the like. Examples of the aromatic hydrocarbon solvent include “Nisseki Clean Sol G” (alkylbenzene) manufactured by Nippon Petroleum Co., Ltd., “Solvesso 200” manufactured by Exxon, and the like. Examples of ester solvents include methyl laurate, isopropyl laurate, hexyl laurate, isopropyl myristate, isopropyl palmitate, isooctyl palmitate, methyl oleate, ethyl oleate, isopropyl oleate, butyl oleate, methyl linoleate, Isobutyl linoleate, ethyl linoleate, isopropyl isostearate, soybean oil methyl, soybean oil isobutyl, tall oil methyl, tall oil isobutyl, diisopropyl adipate, diisopropyl sebacate, diethyl sebacate, propylene glycol monocaprate, tri-2-ethyl Trimethylolpropane hexanoate, glyceryl tri-2-ethylhexanoate, etc .; alcohol solvents include isomyristyl alcohol, isopalmityl alcohol Le, isostearyl alcohol, oleyl alcohol, and the like. Two or more of these solvents can be mixed and used. Preferably, ester solvents, especially isooctyl palmitate and hexyl laurate are used.

  Preferably, the ink includes at least one ionic substance selected from the group consisting of a quaternary ammonium salt, a quaternary phosphonium salt, a combination of a fatty acid and / or an alkyl phosphate ester and an amine compound, and a synergist.

Examples of the cation in the quaternary ammonium salt include ammonium having four hydrocarbon groups having 1 to 24 carbon atoms, such as tetramethylammonium, tetraethylammonium, tetrapropylammonium, triethylmethylammonium, dodecyltrimethylammonium, benzyltrimethylammonium, and the like. Can be mentioned. Examples of anions include hydroxide ions, carbonate ions, carboxylate ions, halogen ions such as Cl ⁻ and Br ⁻ , hydrogen sulfate ions (HSO ₄ ⁻ ), phosphate ions, and the like.

上式中、Ｒ^５、Ｒ^６、Ｒ^７及びＲ^８のうちの２もしくは３個はメチル基で、その他は炭素数１２〜２４のアルキル基もしくはアリール基である、又は、Ｒ^５、Ｒ^６、Ｒ^７及びＲ^８の全てが炭素数３〜５のアルキル基である。アリール基の例としては、フェニル基、ベンジル基などが挙げられる。Ｘは酢酸イオン、ハロゲンイオン、又は硫酸水素イオンである。 Preferably, a quaternary ammonium salt represented by the following formula (3) is used.

In the above formula, 2 or 3 of R ⁵ , R ⁶ , R ⁷ and R ⁸ are methyl groups, and the others are alkyl groups or aryl groups having 12 to 24 carbon atoms, or R ⁵ , R ⁶ , R ⁷ and R ⁸ are all alkyl groups having 3 to 5 carbon atoms. Examples of the aryl group include a phenyl group and a benzyl group. X is an acetate ion, a halogen ion, or a hydrogen sulfate ion.

  Examples of the quaternary ammonium salt represented by the above formula include dimethyldipalmityl ammonium bromide, dimethyl distearyl ammonium bromide, dimethyl distearyl ammonium chloride, tetrabutyl ammonium bromide, tetrabutyl ammonium hydrogen sulfate, stearyl trimethyl ammonium chloride. , Behenyltrimethylammonium chloride, tetradecyldimethylbenzylammonium chloride, di-cured tallow alkyldimethylammonium acetate (the alkyl group is at least one selected from those having 14, 16 and 18 carbon atoms), trioctylmethylammonium chloride, distearyl Examples thereof include dimethylammonium chloride and benzyltributylammonium chloride.

Preferably, in the above formula, two of R ⁵ , R ⁶ , R ⁷ and R ⁸ are methyl groups and the others are alkyl groups or aryl groups having 12 to 24 carbon atoms, such as dimethyldipal Methyl ammonium bromide, dimethyl distearyl ammonium bromide, dimethyl distearyl ammonium chloride, and those in which R ⁵ , R ⁶ , R ⁷ and R ⁸ are all alkyl groups having 3 to 5 carbon atoms, such as tetrabutylammonium bromide, At least one selected from tetrabutylammonium hydrogen sulfate and tetradecyldimethylbenzylammonium chloride is used.

As the quaternary phosphonium salt, those represented by the general formula [R ⁹ ₄ P] ⁺ X ⁻ (where R ⁹ is an alkyl group or an aryl group, and X is as described above) are preferably used. . Examples of the quaternary phosphonium salt include tetraalkylphosphonium halides having an alkyl group having 1 to 6 carbon atoms, such as tetramethylphosphonium chloride, tetraethylphosphonium bromide, tetrabutylphosphonium bromide; aryl groups having 6 to 10 carbon atoms. Examples thereof include tetraarylphosphonium halides such as tetraphenylphosphonium chloride, among which tetrabutylphosphonium bromide is more preferable.

  It is considered that a combination of a fatty acid and / or alkyl phosphate ester (hereinafter sometimes collectively referred to as “acid”) and an amine compound forms an ammonium salt or a similar form to the ammonium salt in the ink. The same effects as the quaternary ammonium salt and the like can be obtained.

  As the fatty acid, those having 9 or more carbon atoms, preferably 12-30, more preferably 14-22 are used. Examples of the fatty acid include decanoic acid, isomyristic acid, hexadecanoic acid, isopalmitic acid, oleic acid, isostearic acid and the like.

  Examples of the alkyl phosphate ester include a monoalkyl acid phosphate represented by the following formula (4) or a dialkyl phosphate represented by the following formula (5).

In the above formula, R ¹⁰ and R ¹¹ represent an alkyl group having 6 to 22 carbon atoms, preferably 8 to 14 carbon atoms.

  Of these, oil-soluble alkyl phosphates are preferably used. Examples of such phosphate esters include isodecyl acid phosphate, 2-ethylhexyl acid phosphate, dibutyl phosphate and the like.

  Examples of the amine compound include aliphatic amines, alicyclic amines, and aromatic amines, preferably aliphatic amines, more preferably dialkylamines and trialkylamines. Most preferably, the alkyl group has 1 to 26 carbon atoms, more preferably 6 to 18 carbon atoms.

  Examples of the dialkylamine and trialkylamine include dioctylamine, dilaurylmethylamine, trioctylamine, dimethyllaurylamine, dimethylmyristylamine, dimethylpalmitylamine and the like.

  The fatty acid and / or alkyl phosphate ester and the amine compound have a molar equivalent ratio [(fatty acid and / or alkyl phosphate ester) / amine compound] of 0.1 to 10.0, preferably 0.3 to 3, most preferably 0. .8 to 1.2. If the molar equivalent ratio is out of this range, the effects of the present invention may not be sufficiently exhibited.

  A synergist is a derivative in which a polar group is introduced into a pigment skeleton. Examples of pigment skeletons include azo pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, isoindoline pigments, benzimidazolone pigments, pyranthrone pigments, thioindigo pigments, and quinophthalone pigments. Examples of the polar group include an alkylamino group, a carboxyl group, a sulfonic acid group, and a phthalimide group. Among these, phthalocyanine pigments, particularly those obtained by introducing a sulfonic acid group, an amino group or the like into the skeleton of copper phthalocyanine blue, such as copper phthalocyanine sulfonate (Solsperse 5000, Solsperse 12000, Solsperse 22000; all manufactured by Nippon Lubrizol Co., Ltd.) Is mentioned.

  The ionic substance is blended in an amount of 0.01 to 10% by mass, preferably 0.05 to 0.5% by mass, based on the total mass of the ink. When added as a combination of a fatty acid and / or alkyl phosphate ester and an amine compound, the total of them is 0.01 to 10% by mass, preferably 0.1 to 3% by mass, particularly preferably 0.3 to 1.%. It is blended at 0% by mass. If the amount of the ionic substance is less than the above lower limit value, a sufficient effect cannot be obtained, and if it exceeds the above upper limit value, the print density may be lowered.

  In addition to the above components, the ink used in the relevant field such as nozzle clogging inhibitor, antioxidant, conductivity modifier, viscosity modifier, surface tension modifier, oxygen absorber, etc. should be used. Can do.

  The suitable range of the viscosity of the ink varies depending on the nozzle diameter of the ejection head of the inkjet recording system, the ejection environment, and the like, but in general, it is preferably 5 to 30 mPa · s at 23 ° C., and 5 to 15 mPa · s. Is more preferable, and is most preferably about 10 mPa · s. Here, the viscosity represents a value at 10 Pa when the shear stress is increased from 0 Pa at a rate of 0.1 Pa / s at 23 ° C.

  The ink jet recording apparatus using the recording paper of the present invention may be of any system such as a piezo system, an electrostatic system, or a thermal system.

  Examples of the present invention will be described below, but the present invention is not limited thereto. In the examples, “%” represents “mass%” and “part” represents “part by mass”.

[Example 1]
Spindle-like light calcium carbonate (trade name: PCX-850) with respect to 100 parts of pulp obtained by mixing hardwood bleached kraft pulp and softwood bleached kraft pulp at a mass ratio of 80:20 and beaten at a Shopper Leaguer freeness of 63 ° , Shiraishi Kogyo Co., Ltd., oil absorption 40 ml / 100 g, average particle size 3.5 μm (measured with a laser diffraction particle size distribution meter manufactured by Shimadzu Corporation)) and 27 parts of an alkyl ketene dimer per unit of paper weight. It was added so as to be 16% by mass to obtain a paper stock. This stock is made with an on-top twin-wire machine, and the oxidized starch is dried at 0.7 g / m ² (1.42% by weight per paper weight) with a size press coater, and the anionic polyacrylamide is dried at a weight of 0.00. The recording paper 1 was prepared by applying a 1-nip machine calendering process with 18 g / m ² (0.37 mass% per paper mass).

[Example 2]
In a size press coater, the oxidized starch is 0.35 g / m ² (0.72% by mass per paper mass) by dry mass, and the anionic polyacrylamide is 0.09 g / m ² (0.19 mass per paper mass) by dry mass. %) Was made in the same manner as the recording paper 1 except that the recording paper 2 was attached.

<Preparation of comparative recording sheet 3>
Oxidized starch at a dry mass of 1.5 g / m ² (2.96% by mass per paper mass) and styrene acrylic resin at a dry mass of 0.36 g / m ² (0.71% by mass per paper mass) A comparative recording paper 3 was prepared in the same manner as the recording paper 1 except that the sticky sizing degree was 8 seconds.

<Preparation of comparative recording sheet 4>
Comparative recording paper 4 in the same manner as recording paper 1 except that only oxidized starch was adhered to a dry weight of 0.8 g / m ² (1.6% by weight per paper weight) with a size press coater. It was created.

[Characteristics of recording paper]
For each recording paper, the basis weight (JIS P 8124), density (JIS P 8118), ash content (JIS P 8251), and steecht size (JIS P 8122) were measured. The results are shown in Table 2.

[Preparation of non-aqueous ink]
(1) Preparation of alkyl (meth) acrylate copolymer A 300 ml four-necked flask was charged with 75 g of AF-4 (naphthenic solvent; manufactured by Nippon Oil Corporation), and aerated with nitrogen gas, The temperature was raised to 110 ° C. Subsequently, 16.7 g of AF-4, perbutyl O (t-butylperoxy 2-ethylhexa) was added to a mixture of 50% by weight of behenyl methacrylate, 35% by weight of 2-ethylhexyl methacrylate and 15% by weight of glycidyl methacrylate while maintaining the temperature at 110 ° C. A mixture of 2 g of Noate (manufactured by NOF Corporation) was added dropwise over 3 hours. Thereafter, 0.2 g of perbutyl O was added after 1 hour and 2 hours while maintaining at 110 ° C. Furthermore, after aging at 110 ° C. for 1 hour, it was diluted with 10.4 g of AF-4 to obtain a colorless and transparent main chain polymer solution having a nonvolatile content of 50%. The weight average molecular weight (GPC method, standard polystyrene conversion) of the obtained polymer was 20000-23000.
Next, in a 500 mL four-necked flask, 81 g of isooctyl palmitate (IOP, manufactured by Nikko Chemicals Co., Ltd.), 200 g of the main chain polymer solution (solid content 50% in AF-4 solvent), 4.0 g of propylene glycol, diethanolamine 2.8 g was charged, and the temperature was raised to 110 ° C. while aerated and stirred with nitrogen gas, and kept at that temperature for 1 hour. Thereafter, 0.2 g of dibutyltin dilaurate was added, and a mixture of Takenate 600 (1,3-bis (isocyanatomethyl) cyclohexane, Mitsui Chemicals Polyurethane Co., Ltd.) 10.2 g and IOP 99 91.8 g was added for 1 hour. It was dripped over. After the dropping, the temperature was raised to 120 ° C. and reacted for 6 hours, followed by cooling to obtain a resin dispersion having a solid content of 30%. The weight average molecular weight (GPC method, standard polystyrene conversion) of the obtained polymer (referred to as “dispersant 1”) was 22000 to 26000, and the urethane bond part amount was 10% by mass.

ＭＡ−１００：カーボンブラック、ＤＢＰ吸油量１００ｃｍ^３／１００ｇ、窒素吸着比表面積１１０ｍ^２／ｇ、三菱化学社製
ソルスパース５０００：銅フタロシアニン誘導体シナジスト、ルブリゾール社製
ＡＦ−４：ナフテン系溶剤、新日本石油社製
Ｖ２１６： アルキル化ポリビニルピロリドン（PVP)、ＩＳＰジャパン社製 (2) According to the prescription (mass%) shown in Table 1 below, the above alkyl (meth) acrylate copolymer, pigment and the like are put in a glass container, and 80 g of zirconia beads (φ0.5 mm) are put in this, and a rocking mill (Seiwa) Non-water-based inks 1 to 4 were prepared by using a RM05S model manufactured by Giken Co., Ltd. for 2 hours at a frequency of 60 Hz.

MA-100: carbon black, DBP oil absorption of 100 cm ^3/100 g, the nitrogen adsorption specific surface area 110m ² / g, manufactured by Mitsubishi Chemical Corporation Solsperse 5000: copper phthalocyanine derivative synergist, Lubrizol Corp. AF-4: naphthene-based solvent, manufactured by Nippon Oil V216: Alkylated polyvinylpyrrolidone (PVP), manufactured by ISP Japan

印刷濃度（裏ΔＯＤ）

[Examples 1-5, Comparative Examples 1-2]
Using the recording paper and ink shown in Table 2, the printing density and the degree of back-through were examined by the following method. The product was loaded into an inkjet printer “ORHPIS X9050” (trade name: manufactured by Riso Kagaku Kogyo Co., Ltd.), and a solid was printed on the above paper in a solid black with a discharge amount of 30 pl per 300 dpi. The front and back surfaces of the obtained solid image and the OD value of white paper were measured using an optical densitometer (RD920, manufactured by Macbeth Co.) and evaluated according to the following criteria. If the OD value on the front side is high, the image density is high, and if the ΔOD on the back side, that is, the value obtained by subtracting the OD value on the back side from the OD value on the back side is 0.14 or less, there is no problem even if both sides are printed. preferable.

Print density (Table OD)

Print density (backside ΔOD)

<Yellowing>
The yellowing of the recording paper was evaluated by the following method.
A 4% 4'-methylenebis-2,6- (di-tert-butylphenol) 1% ethanol solution was dropped onto the blank portion of each unrecorded recording paper and left in an environment of 23 ° C. and 50% for 100 hours.
For blank blank and dropping unit, and measuring the color difference by ^{CIE LAB (L * a * b} *) color system was determined [Delta] b ^*. Yellowing was evaluated according to the following criteria. For the colorimeter, Eye-One iO manufactured by X-Rite was used.
A: Δb ^* <5 and no yellowing is observed.
X: Δb ^* ≧ 5 and yellowing is observed.

As shown in Table 2, the paper lacking the acrylic resin (Comparative Example 2) was markedly yellowed, and the paper having a high degree of steecht size (Comparative Example 1) was severely exposed. On the other hand, the paper of the present invention did not yellow and did not show through. In particular, when printing was performed using an ink (Examples 1 to 3) containing a predetermined dispersant resin, the showthrough was remarkably small. Furthermore, all the papers of the present invention have a basis weight of less than 50 g / m ² and are lightweight.

  The recording paper of the present invention is a lightweight paper suitable for high-speed inkjet printing with little show-through.

Claims (12)

An inkjet recording paper for recording using a non-aqueous ink containing at least a pigment, a solvent, and a pigment dispersant,
Inorganic particles, acrylic resin, starch, and at least one selected from the group consisting of alkyl ketene dimer, alkenyl succinic anhydride, and neutral rosin,
Nice person size, as measured in accordance with JIS P 8122 is Ri 0.1 to 4 Byodea,
JIS basis weight as measured according to P 8124 is 55 g / ^{m 2} Ru following plain paper Der, ink jet recording paper. An inkjet recording paper for recording using a non-aqueous ink containing at least a pigment, a solvent, and a pigment dispersant,
Inorganic particles, acrylic resin, starch, and at least one selected from the group consisting of alkyl ketene dimer, alkenyl succinic anhydride, and neutral rosin,
Nice person size, as measured in accordance with JIS P 8122 is Ri 0.1 to 4 Byodea,
At least one selected from the group consisting of alkyl ketene dimer, alkenyl succinic anhydride, and neutral rosin with respect to the mass of the recording paper is 0.05 to 0.6 mass%, and starch is 0.1 to 1.5 mass%. And an ink jet recording paper containing 0.05 to 0.5% by mass of an acrylic resin . An inkjet recording paper for recording using a non-aqueous ink containing at least a pigment, a solvent, and a pigment dispersant,
Inorganic particles, acrylic resin, starch, and at least one selected from the group consisting of alkyl ketene dimer, alkenyl succinic anhydride, and neutral rosin,
The inorganic particles comprise fusiform light calcium carbonate;
An ink jet recording paper having a Steecht size measured in accordance with JIS P 8122 of 0.1 to 4 seconds. The inkjet recording paper according to claim 3 , which is plain paper having a basis weight measured in accordance with JIS P 8124 of 55 g / m ² or less. At least one selected from the group consisting of alkyl ketene dimer, alkenyl succinic anhydride, and neutral rosin with respect to the mass of the recording paper is 0.05 to 0.6 mass%, and starch is 0.1 to 1.5 mass%. , and 0.05 to 0.5 wt% of an acrylic resin, according to claim 1, 3 and any one Kouki mounting of the ink jet recording paper 4. The inkjet recording paper according to any one of claims 1 to 5 , wherein an ash content measured according to JIS P 8251 is 20 to 35 mass%. The inkjet recording paper according to any one of claims 1 to 6 , wherein the starch is oxidized starch. The ink jet recording paper according to any one of claims 1 to 7 , wherein the acrylic resin is an anionic acrylic resin. An inkjet recording system using inkjet recording paper and non-aqueous ink,
This recording paper contains at least one selected from the group consisting of inorganic particles, acrylic resin, starch, and alkyl ketene dimer, alkenyl succinic anhydride, and neutral rosin, and is measured in accordance with JIS P 8122 The degree is 0.1 to 4 seconds,
The non-aqueous ink includes at least a pigment, a solvent, and 0.1 to 20% by mass of a pigment dispersant of the non-aqueous ink, and the pigment dispersant is an alkyl (meth) acrylate copolymer, An inkjet recording system comprising a side chain or a cross-linked portion containing 12 to 25% by mass of the group and containing 1 to 40% by mass of the copolymer and a repeating unit represented by the following formula (2).

(In the formula (2), ^{R 3} is a divalent hydrocarbon group, ^{R 4} is alkylene or oxyalkylene group having 2 to 20 carbon atoms having 6 to 16 carbon atoms.) The non-aqueous ink comprises 0.01% by mass to 10% by mass of the non-aqueous ink, the group consisting of a quaternary ammonium salt, a quaternary phosphonium salt, a combination of a fatty acid and / or an alkyl phosphate ester and an amine compound, and a synergist. The inkjet recording system according to claim 9 , further comprising at least one ionic substance selected. The inkjet recording system according to claim 10 , wherein the synergist is a copper phthalocyanine derivative. The inkjet recording system according to claim 10 , wherein the quaternary ammonium salt is a tetrabutylammonium salt.