JP6531666B2 - Ink jet recording paper and method of manufacturing the same - Google Patents

Description

  The present invention relates to an inkjet recording sheet and a method of manufacturing the same.

Ink jet printing can print digital information directly on paper or film without making a printing plate, and it is also easy to print variable information.
Heretofore, coated paper having an ink receiving layer containing a pigment has been widely used as ink jet printed paper. However, as the application of ink jet printing is expanded, ink jet printability may be required also for uncoated paper having no ink receiving layer. However, non-coated paper tends to have low ink jet printability, and in particular, paper with small basis weight tends to have lower ink jet printability. For example, when characters or the like are printed by ink jet printing on newsprint paper having no ink receiving layer and having a small basis weight, the printing image tends to be deteriorated due to ink bleeding or the like.
Then, the method of apply | coating the surface treatment liquid which contains a cationic compound on base paper is proposed as a method of improving inkjet printing image quality, without having an ink receptive layer (patent documents 1, 2).

JP 2014-37664 A JP 2012-121292

However, even in the case of inkjet recording paper having no ink receiving layer as described in Patent Documents 1 and 2, good print image quality may not be obtained.
In addition, in the case of an inkjet recording sheet, it is necessary to prevent back-slip in which characters printed by inkjet printing on one side can be seen through on the other side. Furthermore, in the case of ink jet recording paper, it is necessary to prevent the strike-through of the ink which has been ink jet printed and passes through the inside of the paper to the side opposite to the printing surface. However, in the case of the paper having no ink receiving layer, back penetration and strike through tend to occur easily.
When ink jet printing is applied to newspaper printing, it is required to make the color tone of the paper equal to that of commonly used newsprint.
In addition, in the case of newspaper production, there is a bookbinding process that folds at a high speed using a bookbinding machine after the printing process, but when the bookkeeping accuracy decreases and positional deviation occurs in the superposition, it is excluded as a defective product There is something to be done. Therefore, when the inkjet printing is applied to the printing of newsprint, a matching aptitude which can be accurately registered using a binding machine is required.

  Therefore, the present invention is excellent in the printing image quality of ink jet printing even though it does not have an ink receptive layer, can prevent back see-through and strike through, and is suitable for color tone and alignment when used as newsprint. It is an object of the present invention to provide an inkjet recording sheet which is excellent as well as a method for producing the same.

[1] A paper base comprising 90% by mass or more of deinked pulp with respect to all pulps, and an alkyl-modified starch on both sides or one side, a structure represented by the following formula (1) and the following formula (2) An ink jet recording sheet comprising a coated layer containing an amine polymer having at least one of the structures represented by
(HX in Formula (2) is a mineral acid or an organic acid.)

[2] The ink jet recording sheet according to [1], having a basis weight of 16 to 70 g / m ² .
[3] The content of the alkyl-modified starch in the coating layer is 0.3 to 1.0 g / m ² (however, when the coating layer is provided on both sides, the content is an amount per one surface). The inkjet recording sheet according to [1] or [2], which is
[4] The content of the amine polymer in the coating layer is 0.3 to 0.6 g / m ² (however, when the coating layer is provided on both sides, the content is the amount per one surface) The inkjet recording sheet according to any one of [1] to [3], which is
[5] The inkjet recording sheet according to any one of [1] to [4], containing calcium carbonate and having a total ash content of 1.5 to 35.0% by mass.
[6] The ink jet recording sheet according to any one of [1] to [5], which contains a neutral sizing agent consisting of at least one selected from the group consisting of alkenyl succinic anhydride and alkyl ketene dimer.
[7] The inkjet recording sheet according to [6], wherein the content of the neutral sizing agent is 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the total pulp.

[8] A coating step of applying a surface treatment liquid to at least one surface of a base paper containing 90% by mass or more of deinked pulp with respect to all pulps, and a drying step of drying the coated surface treatment liquid The surface treatment liquid contains an alkyl-modified starch and an amine polymer having at least one of a structure represented by the following formula (1) and a structure represented by the following formula (2), and contains a pigment. A method for producing an ink jet recording sheet, wherein the pigment is not contained or the pigment is contained in a range of 2% by mass or less based on the total mass of the solid content in the surface treatment liquid.
(HX in Formula (2) is a mineral acid or an organic acid.)

[9] The ink jet recording paper according to [8], wherein the base paper is selected so that the basis weight of the obtained ink jet recording paper is 16 to 70 g / m ^2, and the coating amount of the surface treatment liquid is adjusted. Production method.
[10] The inkjet recording according to [8] or [9], wherein the content of the alkyl-modified starch in the surface treatment liquid is 40 to 70% by mass with respect to the total mass of the solid content in the surface treatment liquid. Paper manufacturing method.
[11] Any one of [8] to [10], wherein the content of the amine polymer in the surface treatment liquid is 30 to 60% by mass with respect to the total mass of the solid content in the surface treatment liquid The manufacturing method of the inkjet recording paper as described in-.
[12] The method for producing an ink jet recording sheet according to any one of [8] to [11], wherein the base paper contains 2 to 35 parts by mass of calcium carbonate with respect to 100 parts by mass of a pulp solid content.
[13] The inkjet according to any one of [8] to [12], wherein the base paper contains at least one neutral sizing agent selected from the group consisting of alkenyl succinic anhydride and alkyl ketene dimer. Method of manufacturing recording paper.
[14] The method for producing an inkjet recording sheet according to [13], wherein the content of the neutral sizing agent in the base paper is 0.1 to 1.0 parts by mass with respect to 100 parts by mass of the pulp solid content.
[15] In the coating step, any one of [8] to [14], wherein the coating amount of the surface treatment liquid is 0.3 to 2.3 g / m ^{2 in} terms of solid content per one side of the base paper. The manufacturing method of the inkjet recording paper as described in one.

The ink jet recording paper of the present invention is excellent in the printing image quality of ink jet printing even though it does not have an ink receptive layer, can prevent back-slip and back-off, and is suitable for color tone and registration when used as newsprint. It is also excellent in
According to the method for producing an ink jet recording sheet of the present invention, although it does not have an ink receiving layer, the printing image quality of the ink jet printing can be excellent, the back see-through and the strike through can be prevented, and it is used as newsprint It is possible to easily manufacture an inkjet recording sheet which is also excellent in color tone and alignment suitability.

The ink jet recording paper of the present invention comprises a paper substrate, and has a coated layer containing an alkyl-modified starch and an amine polymer on both sides or one side of the ink jet recording paper.
The coating layer is a layer formed by coating and drying a surface treatment liquid containing an alkyl-modified starch and an amine polymer, as described later. That is, the coating layer is a layer containing a component derived from the surface treatment liquid. Therefore, the coating layer contains an alkyl-modified starch and an amine polymer.
The coating layer is mainly formed on the surface of the paper or near the surface of the paper, or both on the surface of the paper and near the surface of the paper. Note that some of the components may penetrate into the interior away from the surface of the paper.
The coating layer does not have to be formed as a uniform film over the entire surface when the sheet is viewed in plan.
By forming the coating layer described above, the fixability of the inkjet ink can be improved.

The basis weight of the ink jet recording sheet is preferably from 16~70g / ^{m 2,} more preferably from 30 to 60 g / ^{m 2,} more preferably from 35~55g / ^{m 2,} 40~50g / ^m Particularly preferred is ² . The basis weight is a value measured according to JIS P 8124: 2011.
If the basis weight of the ink jet recording paper is less than the lower limit, back-slip and back-through may not be prevented, and the ink jet recording paper may be broken or damaged during ink jet printing. On the other hand, when the basis weight of the ink jet recording paper exceeds the upper limit, the weight of the ink jet recording paper becomes heavy, the texture of the light and thin ink jet recording paper can not be obtained, and in particular, it becomes unsuitable as newsprint paper.

The whiteness of the inkjet recording paper is preferably 50 to 60%, more preferably 52 to 58%. The whiteness is a value measured according to JIS P 8148. If the whiteness of the ink jet recording sheet is within the above range, the color tone suitable for newsprint can be obtained.
The opacity of the inkjet recording paper is preferably 80% or more, and more preferably 90% or more. The opacity is a value measured according to JIS P 8149. If the opacity of the ink jet recording sheet is equal to or more than the lower limit value, back-smearing is sufficiently prevented.
The surface electrical resistance of the ink jet recording sheet is preferably 1 GΩ or more, more preferably 5 GΩ or more, and still more preferably 10 GΩ or more. The surface electrical resistance is a value measured using an electrical resistance meter after being conditioned for 4 hours in a temperature and humidity environment of room temperature 23 ° C. and humidity 50%. If the surface electrical resistance of the ink jet recording sheet is equal to or more than the lower limit value, the alignment suitability when the ink jet recording sheet is used as a newsprint sheet is sufficiently excellent.

The paper base used in the present invention contains 90% by mass or more of deinked pulp (DIP) with respect to the total pulp. The content ratio of the deinked pulp is preferably 95% by mass, and more preferably 100% by mass with respect to the total pulp. In addition, in this specification, a mass is a mass of dry solid, unless there is particular notice.
When the content rate of the deinked pulp in the paper base is less than the lower limit value, backset may not be prevented in some cases, and the color tone and texture of the inkjet recording paper become unsuitable as newsprint.
When other pulp than deinked pulp is contained, chemical pulp (softwood bleached kraft pulp (NBKP), hardwood bleached kraft pulp etc. (LBKP)), mechanical pulp or the like can be used as another pulp.

  The pulp used in the present invention is not particularly limited in freeness (CSF), but Canadian Standard Freeness (Freeness) (JIS P 8121-2: 2012 "Pulp-Freeness Test Method-Part 2: It is preferable that it is 250-550 ml, and, as for Canadian standard freeness method ", it is more preferable that it is 300-500 ml. If the freeness of the pulp is within the above range, the paper strength of the ink jet recording paper can be enhanced, and the drying load in the drying step in papermaking can be reduced, and the paper making speed can be increased.

The paper substrate may contain a filler. Examples of the filler include calcium carbonate, white carbon, clay, amorphous silica, talc, titanium oxide and the like. These fillers may be used alone or in combination of two or more. A pigment derived from waste paper contained in deinked pulp can also be used as a filler. Among the above-mentioned fillers, calcium carbonate is preferable because the effect of enhancing the opacity and the effect of enhancing the ink absorbability can be compatible.
Calcium carbonate may be either light calcium carbonate or ground calcium carbonate. The shape of calcium carbonate is not particularly limited, and may be any of, for example, needle shape, column shape, spindle shape, cubic shape, and irregular shape.
When the filler in the paper base material is blended, it is preferable to blend so that the total ash amount in the ink jet recording paper is 1.5 to 35% by mass.

The total ash content in the inkjet recording paper is preferably 1.5 to 35% by mass, more preferably 10 to 30% by mass, and still more preferably 15 to 25% by mass. Here, the total ash content is the combustion residue content of the paper substrate measured according to JIS P8251: 2003, and is the content of the inorganic substance containing the filler.
If the total ash content in the inkjet recording sheet is above the lower limit value, back penetration can be further prevented, and if it is below the above upper limit value, contamination of the inkjet recording sheet manufacturing apparatus can be suppressed, and the paper of the inkjet recording sheet Force drop can be prevented.

The paper base preferably contains at least one neutral sizing agent selected from the group consisting of alkenyl succinic anhydride and alkyl ketene dimer. When the neutral sizing agent is contained, the hydrophobicity of the paper base can be enhanced and the ink can be further prevented from passing through.
Among the above-mentioned neutral size agents, alkenyl succinic anhydride is more preferable in that the ink is more excellent in the strike-through prevention property.
The content of the neutral sizing agent in the ink jet recording sheet is preferably 0.1 to 2.0 parts by mass, and more preferably 0.5 to 1.5 parts by mass with respect to 100 parts by mass of the entire pulp. . When the content of the neutral sizing agent is equal to or more than the lower limit value, the ink can be further prevented from passing through. However, when the content of the neutral sizing agent exceeds the above upper limit value, the production apparatus for producing the ink jet recording paper tends to be soiled, and the frequency of maintenance tends to increase.

The alkyl-modified starch contained in the coating layer is a starch containing an alkyl group by modification. The alkyl groups make the starch more hydrophobic.
The carbon number of the alkyl group is preferably 4 or more, and more preferably 6 or more, from the viewpoint of enhancing the hydrophobicity to further improve the ink penetration prevention property. On the other hand, it is preferable that carbon number of an alkyl group is 18 or less from the point of the ease of introduction | transduction of the alkyl group to starch.
As an alkyl group, methyl group (carbon number 1), ethyl group (carbon number 2), propyl group (carbon number 3), butyl group (carbon number 4), pentyl group (carbon number 5), hexyl group (carbon number) 6), heptyl group (carbon number 7), octyl group (carbon number 8), nonyl group (carbon number 9), decyl group (carbon number 10), undecyl group (carbon number 11), dodecyl group (carbon number 12) And octadecyl groups (having 18 carbon atoms).
As a method of obtaining an alkyl-modified starch, for example, a method of subjecting an unmodified starch as a raw material to oxidation treatment using an oxidation catalyst to prepare an oxidized starch and then subjecting the oxidized starch to a treatment of introducing an alkyl group Can be mentioned. The type of raw material starch is not particularly limited, but corn starch is preferable from the viewpoint of the suppression of tackiness when wet.

The content of the alkyl-modified starch in the coating layer is preferably from 0.3 to 1.0 g / ^{m 2,} and more preferably 0.5 to 1.0 g / ^{m 2.} However, when the ink jet recording sheet has a coating layer on both sides, the content is an amount per one side.
If the content of the alkyl-modified starch in the coating layer is equal to or more than the lower limit, it is possible to further improve the ink strike-through prevention property and the registration aptitude. Can.

The amine polymer contained in the coating layer has at least one of the structure represented by the formula (1) and the structure represented by the formula (2). The amine polymer functions as an ink fixing agent.
HX in Formula (2) is a mineral acid or an organic acid. Examples of mineral acids include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, carbonic acid and the like. As an organic acid, monobasic acid (for example, acetic acid, lactic acid, gluconic acid etc.), dibasic acid (for example, maleic acid, fumaric acid etc.), polybasic acid (for example, tartaric acid etc.) etc. are mentioned. These acids may be used alone or in combination of two or more. Among the above-mentioned acids, phosphoric acid, hydrochloric acid and lactic acid are preferable.
Examples of amine polymers having both the structure represented by the above formula (1) and the structure represented by the above formula (2) include dicyandiamide-polyalkylenepolyamine condensates, polyalkylenepolyamine dicyandiamide ammonium salt condensates, dicyandiamide -Formaldehyde condensate etc. are mentioned.
When an amine-based polymer having at least one of the structure represented by the above formula (1) and the structure represented by the above formula (2) comes into contact with the water in the ink, the ink jet ink discharged from the printer , A protonated + 1-valent cationic substance. Therefore, the amine-based polymer can easily form an ink jet dye ink having an anionic substance as a coloring material, and an ink jet pigment ink having coloring material particles surface-treated with an anionic substance and dispersed and stabilized by ionic bonding. It can be captured. Therefore, the amine polymer has a function as an ink fixing agent for fixing the ink jet dye ink and the ink jet pigment ink in the vicinity of the surface of the paper.
Further, although the reason is not clear, since the electric resistance value of the ink jet recording sheet is not excessively lowered even if the amine polymer adheres or is impregnated, newspaper magazine suitability is given.

The dicyandiamide-polyalkylenepolyamine condensate can be obtained, for example, by condensation polymerization of a polyalkyleneamine and dicyandiamide and, if necessary, adding a mineral acid or an organic acid.
Examples of polyalkylene amines include ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, propylene diamine, dipropylene triamine and the like. These polyamines may be used alone or in combination of two or more.
Examples of the dicyandiamide-polyalkylenepolyamine condensate include Neofix E-117 (mass average molecular weight 2,500) manufactured by Nikka Chemical Co., Ltd.

The mass average molecular weight of the amine polymer is preferably 1,000 to 10,000, more preferably 1,200 to 4,000, and further preferably 1,500 to 3,500. Preferably, it is 1,800 to 2,800. If the mass average molecular weight of the amine polymer is within the above range, the permeability and barrier properties of the ink in the coating layer can be controlled to an appropriate range, and ink penetration can be further suppressed, and the ink Absorbency can also be enhanced, and print quality can be improved.
The mass average molecular weight is a value measured by gel permeation chromatography under the following measurement conditions.
Solvent: Water distilled water Column: OHpak SB-806 M HQ Shodex is connected and used Column temperature: 40 ° C
Sample concentration: 0.1% by mass
Detector: 1200 series detector (manufactured by Agilent Technology Co., Ltd.)
Pump: 1200 series detector (manufactured by Agilent Technology Co., Ltd.)
Flow rate: 0.5 ml / min
Calibration curve: A calibration curve prepared using six samples having a mass average molecular weight of 1,000 to 20,000 of Shodex Standard P-82 (Pulllan) (manufactured by Showa Denko KK) is used.

The cationization degree of the amine polymer is preferably 0.1 to 15 meq / L, more preferably 0.5 to 13 meq / L, and still more preferably 1 to 10 meq / L. If the degree of cationization of the amine polymer is equal to or higher than the lower limit value, ink penetration can be further suppressed, and if it is equal to or lower than the upper limit value, ink drying properties can be improved.
The degree of cationization is determined by the following method.
The polymer as a sample is dissolved in water to obtain a solution with a polymer concentration of 1 ppm. To the solution, sodium polyethylene sulfonate of known concentration is dropped to measure the charge amount. Then, the amount of charge per liter of solution is determined, and the value is defined as the degree of cationization.

The content of the amine polymer in the coating layer is preferably from 0.3-0.6 g / ^{m 2,} and more preferably 0.45~0.55g / ^{m 2.} However, when the ink jet recording sheet has a coating layer on both sides, the content is an amount per one side.
If the content of the amine-based polymer in the coating layer is the above lower limit or more, the ink penetration prevention property and the alignment aptitude can be further improved, and if it is the above or less upper limit, the ink absorbability and the ink drying It is possible to improve the quality.

  The coating layer contains a starch other than the alkyl-modified starch, a polyvinyl alcohol, and an ink fixing agent other than the amine polymer (for example, a polyamine / epichlorohydrin copolymer etc.) within the range not impairing the object of the present invention. May be

  The coating layer may optionally contain various additives other than the alkyl-modified starch and the amine polymer. Examples of additives include styrene polymers, acidic sizing agents, surfactants, pH regulators, viscosity regulators, softeners, gloss imparting agents, waxes, dispersants, flow modifiers, stabilizers, and charging agents. Examples include inhibitors, crosslinking agents, ultraviolet light absorbers, antifoaming agents, water resistance agents, plasticizers, lubricants, preservatives and perfumes.

  The method for producing an inkjet recording sheet of the present invention includes a coating step of coating a surface treatment liquid on at least one surface of a base paper, and a drying step of drying the coated surface treatment liquid.

The base paper contains 90% by mass or more of the deinked pulp based on the total pulp, as in the above-described paper base. Further, the base paper preferably contains the above-mentioned neutral sizing agent.
The base paper preferably contains 2 to 35 parts by mass, more preferably 8 to 25 parts by mass of calcium carbonate, and more preferably 13 to 23 parts by mass with respect to 100 parts by mass of the pulp solid content. preferable. If the content of calcium carbonate is equal to or more than the above lower limit value, back penetration can be further prevented and ink absorbability can be further improved. On the other hand, when the content of calcium carbonate is equal to or less than the above upper limit, it is possible to suppress the contamination of the manufacturing apparatus of the inkjet recording paper, and to prevent the paper strength decrease of the inkjet recording paper be able to.
In addition, paper stock chemicals such as internal sizing agents other than neutral sizing agents, fixing agents such as sulfuric acid bands, paper strength agents, retention improvers, water resistance agents, binders such as polyvinyl alcohol and starch, etc. It may be included.

The surface treatment liquid contains the alkyl-modified starch and the amine polymer and is a liquid not containing a pigment, or 2 even with respect to the total mass of solids in the surface treatment liquid even if it contains a pigment. It is a liquid contained in the range of mass% or less. If the surface treatment liquid contains more than 2% by mass of the pigment, the texture close to newsprint may be lost, and furthermore, it may cause stains in the apparatus for manufacturing inkjet recording paper.
As the dispersion medium contained in the surface treatment liquid, for example, water, alcohol solvents, ether solvents, ketone solvents and the like can be used, and among these, water is preferable in terms of cost.
In addition, the surface treatment liquid may contain various additives to be contained in the coating layer.

The content of the alkyl-modified starch in the surface treatment liquid is preferably 40 to 70% by mass, and more preferably 50 to 65% by mass with respect to the total mass of the solid content in the surface treatment liquid. More preferably, it is 55 to 65% by mass. If the content of the alkyl-modified starch in the surface treatment liquid is equal to or more than the lower limit, the ink anti-slip property and the alignment aptitude can be further improved, and if the content is equal to or less than the upper limit, the ink drying is improved. be able to.
It is preferable that it is 30-60 mass% with respect to the total mass of solid content in the said surface treatment liquid, and, as for content of the amine polymer in the said surface treatment liquid, it is more preferable that it is 30-55 mass% And 35 to 45% by mass. If the content of the amine polymer in the surface treatment liquid is not less than the above lower limit value, the ink penetration preventing property and the alignment aptitude can be further improved, and if it is not more than the above upper limit value, the ink absorbability and the ink Drying can be improved.

In the method for producing an ink jet recording sheet of the present invention, the base paper is selected so that the basis weight of the ink jet recording sheet obtained is 16 to 70 g / m ² in the coating step, and the surface treatment liquid is applied. It is preferred to adjust the amount.
Specifically, in the coating step, the coating amount of the surface treatment liquid is preferably 0.3 to 2.3 g / m ^{2 in} terms of solid content per one side of the base paper, and 0.5 to 2.0 g /, more preferably to ^{m 2,} and even more preferably to a 1.0 to 1.5 g / ^{m 2.} If the application amount of the surface treatment liquid is equal to or more than the lower limit, the fixability of the ink can be imparted, and if it is equal to or less than the upper limit, the texture of low basis weight, particularly the texture of newspaper etc. it can.
In the selection of the base paper, the basis weight of the base paper, the content of the filler such as calcium carbonate, the content ratio of the deinked pulp, and the deinked pulp so that the basis weight of the inkjet recording paper is 16 to 70 g / m ² The base paper is selected in consideration of the type of pulp and so on.

  The coating apparatus that can be used in the coating step is not particularly limited, and, for example, a roll coater (for example, 2 roll size press, blade metering size press, rod metering size press, gate roll coater, etc.), blade coater (trailing, Flexible, roll application, fountain application, bevel type or short type blade coater such as short dwell, or rod blade coater, bar coater, air coater, curtain coater, spray coater, gravure coater, etc. can be used. In the coating step, it is preferable to apply the surface treatment liquid using a size press provided in the paper machine, because the productivity is excellent.

In the drying step, for example, various drying methods such as steam drying, gas heater drying, electric heater drying, infrared heater drying and the like can be adopted.
After the drying step, smoothing processing may be performed using various calender devices.
As the calender apparatus, for example, a super calender, a soft calender, a gloss calender, a compact calender, a matte super calender, a matte calender, or the like can be used.

As described above, the inkjet recording paper in the present invention has a coated layer containing the alkyl-modified starch and the amine polymer on at least one surface of a paper base containing 90% by mass or more of deinked pulp. It is a thing.
When the deinked pulp content in the paper base is 90% by mass or more, the ink jet recording paper of the present invention has high anti-backing properties, and has a color tone equivalent to that of commonly used newsprint paper. Have.
In paper containing a large amount of deinked pulp, the content of impurities such as hydrophobic substances and hydrophilic substances is high, and feathering (fuzzing in the printing outline) and voids (white spots in the printing area) when ink jet printing is performed ) Are prone to occur. However, since the amine polymer has a high effect of fixing an ink (particularly, pigment ink), the ink jet recording sheet of the present invention having the coating layer containing the amine polymer is not much influenced by impurities. , Feathering and voids can be suppressed. Therefore, since it is easy to print as desired, it is excellent in print image quality. Furthermore, since the ink-fixing property of the amine polymer is high, it is possible to increase the anti-backout property of the ink on the ink jet recording sheet.
In addition, the amine polymer increases the surface resistance of the ink jet recording sheet to facilitate the generation of static electricity. In the case of a bookbinding machine that folds and stacks paper, electrostatic attraction may be used when transporting the paper, and paper that is susceptible to static electricity is suitable. Therefore, the inkjet recording sheet of the present invention, in which static electricity is easily generated by the amine polymer, is highly suitable for registration.
In general, amine compounds tend to have a strong odor, but the amine polymers have a weak odor. Therefore, in the ink jet recording sheet of the present invention, the working environment for printing can be improved, and the odor of the printed matter can be improved.
In the ink jet recording paper of the present invention, the hydrophobic property of the paper surface is enhanced by the coating layer containing the alkyl modified starch. When the paper surface has high hydrophobicity, ink bleeding can be suppressed, and thin line reproducibility will be high, so that the printing image quality will be good. In addition, since oxidized starch, esterified starch or etherified starch is low in hydrophobicity, ink bleeding can not be sufficiently suppressed, and thin line reproducibility tends to be low, so that print image quality is unlikely to be good.
Further, since the alkyl-modified starch and the amine polymer are excellent in compatibility, they are uniformly dispersed in the coated layer, and each function can be sufficiently exhibited.

  The inkjet recording paper of the present invention is suitable as newsprint paper, but is not limited to newsprint paper, and utilizes its thin and light characteristics, for example, various applications such as notebook paper, dictionary paper, manual paper, etc. It can be used for

Hereinafter, the present invention will be more specifically described by showing Examples and Comparative Examples. However, the present invention is not limited to the following examples.
The degree of cationization in the following examples was determined by the following method.
The polymer as a sample was dissolved in water to obtain a solution with a polymer concentration of 1 ppm. To the solution, using a charge analyzer Mutek PCD-04 manufactured by BTG, 0.001 N polyethylene sulfonate sodium was dropped, and the charge amount was measured. Then, the amount of charge per liter of solution was determined, and the value was defined as the degree of cationization.

Example 1
"Preparation of stock"
The deinked pulp is disintegrated to give a freeness of 400 ml C.I. S. F. And 1 part by mass of sulfuric acid band, 1 part by mass of cationized starch (Ace K-100 manufactured by Oji Cornstarch Co., Ltd.) and 100 parts by mass of disaggregated pulp, alkenyl succinic anhydride (manufactured by Arakawa Chemical Industry Co., Ltd.) as internal sizing agent 0.3 parts by mass of size pine SA-864 (denoted as "ASA" in the table) was added. Thereafter, 20 parts by mass of calcium carbonate was mixed as a filler, and 0.011 part by mass of a retention aid (Keiwa Lock RP40L manufactured by Kyowa Sangyo Co., Ltd., polyacrylamide) was further added to obtain a stock.

"Preparation of surface treatment solution"
In water, 60 parts by mass of alkyl-modified starch (GRS-T110 manufactured by Oji Cornstarch Co., Ltd., described as "GRS" in the table), 1 part by mass of a surface sizing agent (SE2220 manufactured by Hoshimitsu PMC Co., Ltd.) Amine polymers having a structure represented by 1) and a structure represented by formula (2) (Neofa Chemical Co., Ltd., Neofix E-117, mass average molecular weight: 2,500, degree of cationization 4. A surface treatment liquid with a solid content concentration of 4% by mass was obtained by adding 0 meq / L (denoted as "E-117" in the table) in a proportion of 40 parts by mass. In addition, the mass part number of each component of surface treatment liquid is the number of parts which made the pulp of the said base paper 100 mass parts.

"Preparation of inkjet recording paper"
The prepared stock is made into a base paper by using a Fourdrinier multi-tubular paper machine so that the basis weight becomes 42 g / m ² , to obtain a base paper, and using a two-roll size press in the Four-hundred multifilamentary paper machine The surface treatment solution was applied to both sides of the base paper so that the dry coating amount was 1.3 g / m ² per one side. Thereafter, it was dried at 130 ° C. using a hot air drier in a Fourdrinier multi-layered paper machine, to obtain an inkjet recording sheet having a coating layer.
The content of the alkyl-modified starch, the content of the amine polymer, and the content of the surface sizing agent per one side in the coating layer are shown in Table 1. In addition, also about the other Example and comparative example, content of the content of the starch per single side in an application layer, content of an amine polymer, and content of a surface sizing agent are shown to Tables 1-3.

(Example 2)
An inkjet recording sheet having a coating layer was obtained in the same manner as in Example 1 except that the surface treatment solution obtained without adding the surface sizing agent was used.

(Example 3)
An inkjet recording sheet having a coating layer was obtained in the same manner as in Example 1 except that the dry coating amount per one surface of the surface treatment liquid was changed to 0.3 g / m ² .

(Example 4)
An inkjet recording sheet having a coating layer was obtained in the same manner as in Example 1 except that the dry coating amount per one surface of the surface treatment liquid was changed to 2.3 g / m ² .

(Example 5)
An inkjet recording sheet having a coating layer was obtained in the same manner as in Example 1 except that the amount of the alkyl-modified starch added to the surface treatment liquid was 78 parts by mass and the amount of the amine polymer was changed to 22 parts by mass. .

(Example 6)
An inkjet recording sheet having a coated layer was obtained in the same manner as in Example 1 except that the amount of the alkyl-modified starch added to the surface treatment liquid was 34 parts by mass, and the amount of the amine polymer added was 66 parts by mass. .

(Example 7)
An inkjet recording sheet having a coated layer was obtained in the same manner as in Example 1 except that the content of calcium carbonate in the base paper was changed to 2 parts by mass.

(Example 8)
An inkjet recording sheet having a coated layer was obtained in the same manner as in Example 1 except that the content of calcium carbonate in the base paper was changed to 35 parts by mass.

(Example 9)
An inkjet recording sheet having a coating layer was obtained in the same manner as in Example 1 except that the content of the internally added sizing agent in the base paper was changed to 0.5 parts by mass.

(Example 10)
An inkjet recording sheet having a coated layer was obtained in the same manner as in Example 1 except that the content of the internally added sizing agent in the base paper was changed to 0.05 parts by mass.

(Example 11)
Same as Example 1 except that the internal sizing agent in the base paper is changed to 0.3 parts by mass of alkyl ketene dimer (size pine K-287 manufactured by Arakawa Chemical Industries, Ltd., denoted as "AKD" in the table) To obtain an ink jet recording sheet having a coating layer.

(Example 12)
An inkjet recording sheet having a coated layer was obtained in the same manner as in Example 1 except that the basis weight of the base paper was changed to 15 g / m ² .

(Example 13)
An inkjet recording sheet having a coated layer was obtained in the same manner as in Example 1 except that the basis weight of the base paper was changed to 67 g / m ² .

(Example 14)
An ink jet recording sheet having a coating layer was obtained in the same manner as in Example 1 except that the pulp constituting the base paper was changed to 90 parts by mass of deinked waste paper pulp and 10 parts by mass of hardwood bleached kraft pulp.

(Comparative example 1)
An inkjet recording sheet having a coated layer was obtained in the same manner as in Example 1 except that the amount of the alkyl-modified starch in the surface treatment liquid was changed to 100 parts by mass and the amount of the amine polymer was changed to 0 parts by mass. .

(Comparative example 2)
The amine-based polymer is polydiallyldimethyl ammonium chloride (Unense CP-103 manufactured by Senka Co., Ltd., weight average molecular weight 140,000, degree of cationization 3.1 meq / L, denoted as "CP-103" in the table). An inkjet recording sheet having a coating layer was obtained in the same manner as in Example 1 except that the above was changed to.

(Comparative example 3)
The amine polymer was changed to a polyamine-epichlorohydrin copolymer (DK6802 manufactured by Starlight PMC Co., Ltd., weight average molecular weight 1,000, degree of cationization 3.2 meq / L, represented as "DK6802" in the table). An ink jet recording sheet having a coating layer was obtained in the same manner as Example 1 except for the above.

(Comparative example 4)
An ink jet recording sheet having a coated layer is obtained in the same manner as in Example 1 except that the alkyl-modified starch is changed to oxidized starch (Ace manufactured by Oji Cornstarch Co., Ltd., denoted as "Ace A" in the table). The

(Comparative example 5)
An ink jet recording sheet having a coating layer was obtained in the same manner as in Example 1 except that the alkyl-modified starch was changed to polyvinyl alcohol (PVA-117 manufactured by Kuraray Co., Ltd., denoted as "PVA" in the table). .

(Comparative example 6)
A mixture 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 bleached kraft pulp is deaggregated to give a freeness of 400 ml C.I. S. F. And 1 part by mass of sulfuric acid band, 1 part by mass of cationized starch (Ace K-100 manufactured by Oji Cornstarch Co., Ltd.), 100 parts by mass of this disintegrated pulp, and alkenyl succinic anhydride (manufactured by Arakawa Chemical Industries, Ltd.) as internal sizing agent 0.3 parts by weight of size pine SA-864) was added. Thereafter, 20 parts by mass of calcium carbonate was mixed as a filler, and further 0.011 parts by mass of a retention aid (Keiwa lock RP40L manufactured by Kyowa Sangyo Co., Ltd., polyacrylamide) was added. The stock thus prepared was used to make a basis weight of 42 g / m ² using a fourdrinier multi-layered paper machine to obtain a base paper.
An inkjet recording sheet having a coating layer was obtained in the same manner as in Example 1 except that the base paper was used.

<Evaluation>
The ink jet recording paper obtained in each Example and Comparative Example was evaluated by the method shown below. The obtained results are shown in Tables 1 to 3.

[Basic weight]
The basis weight of the inkjet recording paper obtained in each example was measured according to JIS P 8124: 2011.

[ash]
The ash content of the ink jet recording paper obtained in each example was measured according to JIS P 8251: 2003.

[Whiteness]
The whiteness of the inkjet recording paper obtained in each example was measured according to JIS P 8148. Generally, the whiteness of newsprint is in the range of 52 to 58%.

Opacity
The opacity of the inkjet recording paper obtained in each example was measured according to JIS P 8149.

[Surface resistance]
The ink jet recording paper obtained in each example was conditioned for 4 hours in a temperature and humidity environment of room temperature 23 ° C. and humidity 50%, and then surface electrical resistance was measured using an electrical resistance meter R8340A manufactured by Advantest Corporation. If the surface electrical measurement value is 1 GΩ or more, there is no problem in practical use.

[Print Quality / Bleeding Prevention]
A barcode of GS1-128 code was printed on one side of the ink jet recording paper obtained in each example using an ink jet printer (ColorStream 3900 manufactured by Canon Production Printing System Co., Ltd.).
Subsequently, the bar code reader was scanned 10 times using the bar code verifier (Inspector D4000 manufactured by RJS) on the ink jet recording paper on which the bar code was printed. At that time, the number of times the bar code was read was measured and evaluated based on the following criteria.
(Evaluation criteria)
5: Within 10 scans of the barcode reader, it can be read 10 times.
4: 9 out of 10 scans of a barcode reader.
3: Among the 10 scans of the barcode reader, 6 or more and less than 9 can be read.
2: Within 10 scans of the barcode reader, the number of readings is less than 5 or reading can be made by passing a plurality of laser scanning lines to the barcode even if the number of readings is 0.
1: The barcode can not be read.
In addition, it is excellent in the printing image quality by inkjet printing, and it means being excellent in inkjet printability, so that the numerical value of evaluation is large. If the evaluation is 3 or more, there is no problem in practical use.

[Print image quality / thin line reproducibility]
Using an inkjet printer (ColorStream 3900 manufactured by Canon Production Printing System Co., Ltd.), 6-point gothic characters were printed on one side of the inkjet recording sheet obtained in each example. The printed characters were “1”, “2”, “3”, “4”, “5”, “6”, “7”, “8”, “9”, “10”. The printed characters were visually observed, and the reproducibility of thin lines was evaluated according to the following criteria.
(Evaluation criteria)
5: There is no bleeding or crushing in the thin line portion of the number, and there is no influence on the determination of the number.
4: There is a slight amount of bleeding or crushing in the thin line portion of the number but there is no influence on the discrimination of the number.
3: Bleeding or crushing occurs in the thin line portion of the numbers, but all numbers can be identified.
2: Bleeding or crushing occurs in the thin line portion of numbers, and some numbers such as “4”, “6”, “8”, “9”, “0” can not be determined.
1: Bleeding or crushing occurs in the thin line portion of numbers, and all numbers can not be determined.
In addition, it is excellent in the printing image quality by inkjet printing, and it means being excellent in inkjet printability, so that the numerical value of evaluation is large. If the evaluation is 3 or more, there is no problem in practical use.

[Anti-crossover]
On both sides of the ink jet recording paper obtained in each example, “color digital standard image data / N3” published by Japan Standards Association was printed using an ink jet printer (ColorStream 3700Z manufactured by Canon Production Printing System Co., Ltd.).
Then, visually observe each solid printed portion of black, cyan, magenta, and yellow, that is, the surface on the side opposite to the printed surface (hereinafter referred to as “printed reverse surface”) of the portion printed without gaps. The degree of transfer of the printing ink to the reverse side of the printing (degree of strikethrough) was evaluated according to the following criteria.
(Evaluation criteria)
5: There is no transfer of printing ink to the reverse side of printing, and there is no influence on the reverse side of printing.
4: Slight transfer of printing ink to the reverse side of the print is observed, but the reverse side of the print is not affected.
3: Transfer of printing ink to printing reverse side is observed, but the image on the reverse side of printing is not damaged.
2: Transfer of printing ink to printing reverse side is observed, and the image on the reverse side of printing is lost.
1: A significant migration of printing ink to the reverse side of printing is observed.
In addition, if evaluation is three or more, there is no problem in practical use.

[Anti-backout]
On one side of the ink jet recording paper obtained in each example, “color digital standard image data / N3” published by Japan Standards Association was printed using an ink jet printer (ColorStream 3700Z manufactured by Canon Production Printing System Co., Ltd.).
Then, each solid printed portion of black, cyan, magenta, and yellow, that is, the printed back surface of the portion printed without a gap was visually observed, and the extent to which the printing ink could be seen to penetrate (the degree of back penetration) was evaluated.
Evaluation was made into five steps, and it was evaluated that back penetration prevention property is high, so that a numerical value is large. In addition, if evaluation is "3" or more, there is no problem in practical use.

[Color tone]
The ink jet recording paper obtained in each example was compared with newsprint paper (SL newsprint paper) manufactured by Oji Paper Co., Ltd., and the difference in color tone was visually evaluated according to the following criteria.
(Evaluation criteria)
5: The apparent color is almost the same as that of newsprint.
4: There is a slight difference between newsprint and apparent color, but there is no practical problem as newsprint.
3: There is a difference between newspaper paper and apparent color, but there is no practical problem as news paper.
2: There is a clear difference between newsprint and apparent color, and there is a practical problem as newsprint.
1: There is a large difference between newsprint and apparent color, and there is a problem in practical use as newsprint.
In addition, if evaluation is "3" or more, there is no problem in practical use.

[Booking aptitude]
The ink jet recording paper obtained in each example is conditioned for 4 hours in a temperature and humidity environment of a room temperature of 23 ° C. and a humidity of 50%, and then the paper is folded and stacked using a newspaper register machine (DC7 manufactured by HUNKELER) The Then, the degree of paper deviation after registration was evaluated by visual observation.
The evaluation was made in five steps, and the larger the value, the smaller the paper misregistration and the more suitable it was. In addition, if evaluation is "3" or more, there is no problem in practical use.

[Ink drying property]
Using an ink jet printer (ColorStream 3900 manufactured by Canon Production Printing System Co., Ltd.), eight-point gothic characters were printed on one side of the ink jet recording paper obtained in each example. The printed characters were “1”, “2”, “3”, “4”, “5”, “6”, “7”, “8”, “9”, “10”.
And the transfer stain | pollution | contamination of the ink in the paper surface which carried out the inkjet printing was observed visually, and the following references | standards evaluated. The ink transfer stains are stains that are caused by the undried ink adhering to the roller of the printing machine and the like and the adhered ink being transferred to the paper. The transfer stain is more likely to occur as the ink drying property of the paper is lower.
(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 influence on the discrimination of the numbers.
3: There is a transfer stain, but all numbers can be identified.
2: There is a transfer stain, and it is impossible to distinguish some numbers such as "4", "6", "8", "9", "0", etc.
1: There is a transfer stain, and all numbers can not be determined.
In addition, if evaluation is three or more, the drying property of printing is high and there is no problem practically.

[Abrasion resistance]
Using an ink jet printer (ColorStream 3900 manufactured by Canon Production Printing System Co., Ltd.), eight-point gothic characters were printed on one side of the ink jet recording paper obtained in each example. The printed characters were “1”, “2”, “3”, “4”, “5”, “6”, “7”, “8”, “9”, “10”.
Then, the printed surface was rubbed ten times with a cloth, and the degree of rubbing stains on the printed portion was visually observed and evaluated according to the following criteria.
(Evaluation criteria)
5: There is no rubbing stain and there is no influence on the discrimination of the number.
4: There are slight stains, but there is no influence on the discrimination of numbers.
3: There are rubbing stains, but all numbers can be identified.
2: There are rubbing stains, and some numbers such as “4”, “6”, “8”, “9” and “10” can not be determined.
1: There are rubbing stains and all numbers can not be determined.
In addition, there is no problem in practical use, if it is excellent in abrasion resistance and evaluation is three or more, so that the numerical value of evaluation is large.

[Printing uniformity]
On one side of the ink jet recording paper obtained in each example, “color digital standard image data / N3” published by Japan Standards Association was printed using an ink jet printer (ColorStream 3900 manufactured by Canon Production Printing System Co., Ltd.).
And the printing nonuniformity of the solid printing part of each of black, cyan, magenta, and yellow, ie, the part printed without gap, was visually observed, and the following references evaluated.
(Evaluation criteria)
5: There is no printing unevenness and there is no influence on the image.
4: There is slight printing unevenness, but the image is not affected.
3: There is printing unevenness, but the image is not damaged.
2: There is printing unevenness and the image is lost.
1: There is significant printing unevenness.
The larger the numerical value of the evaluation, the better the printing uniformity. If the evaluation is 3 or more, there is no problem in practical use.

In each example, a surface treatment liquid containing an amine polymer having a structure represented by Formula (1) and a structure represented by Formula (2) and an alkyl-modified starch is used as a base paper of 100 parts by mass of deinked pulp. The coating was applied to obtain an inkjet recording sheet. The ink jet recording paper obtained in each Example was excellent in all of the printing image quality, the strikethrough prevention property, the backset prevention property, the newspaper color tone and the registration suitability.
In Comparative Example 1 in which the surface treatment liquid containing no amine polymer was used, all of the printing image quality of the obtained ink jet recording sheet, the anti-backout property, and the anti-backout property were low.
In Comparative Example 2 using the surface treatment liquid containing polydiallyldimethyl ammonium chloride instead of the amine polymer having the structure represented by the formula (1) and the structure represented by the formula (2), the obtained inkjet The aptitude of the recording paper was low.
In Comparative Example 3 using a surface treatment solution containing a polyamine / epichlorohydrin copolymer instead of the amine polymer having the structure represented by the formula (1) and the structure represented by the formula (2), The print quality of the ink jet recording paper and the matching suitability were low.
In Comparative Example 4 in which a surface treatment solution containing oxidized starch was used instead of the alkali-modified starch, the print quality of the obtained inkjet recording paper was low.
In Comparative Example 5 in which a surface treatment solution containing polyvinyl alcohol instead of alkali-modified starch was used, the print quality of the obtained inkjet recording paper was low.
In Comparative Example 6 in which the deinking pulp content of the base paper was 60 parts by mass, the ink jet recording paper obtained was low in the strikethrough prevention property and the reverse penetration prevention property, and the color tone was not close to newspaper color.

Claims (15)

It consists of a paper base containing 90% by mass or more of deinked pulp with respect to all pulps, and is represented by an alkyl-modified starch, a structure represented by the following formula (1) and a following formula (2) on both sides or one side. An ink jet recording sheet comprising a coating layer containing an amine polymer having at least one of the following structures.

(HX in Formula (2) is a mineral acid or an organic acid.) Basis weight of 16~70g / ^{m 2,} the ink jet recording sheet according to claim 1. The content of the alkyl-modified starch in the coated layer is 0.3 to 1.0 g / m ² (however, when the coated layer is provided on both sides, the content is the amount per one side). An ink jet recording sheet according to claim 1 or 2. The content of the amine polymer in the coating layer is 0.3 to 0.6 g / m ² (however, when the coating layer is provided on both sides, the content is an amount per one surface). The ink jet recording sheet according to any one of claims 1 to 3, wherein   The ink jet recording sheet according to any one of claims 1 to 4, which contains calcium carbonate and has a total ash content of 1.5 to 35.0% by mass.   The ink jet recording sheet according to any one of claims 1 to 5, containing a neutral sizing agent consisting of at least one selected from the group consisting of alkenyl succinic anhydride and alkyl ketene dimer.   The ink jet recording sheet according to claim 6, wherein the content of the neutral sizing agent is 0.1 to 2.0 parts by mass with respect to 100 parts by mass of total pulp. Including a coating step of coating the surface treatment liquid on at least one surface of the base paper containing 90% by mass or more of deinked pulp with respect to the total pulp, and a drying step of drying the coated surface treatment liquid;
The surface treatment liquid contains an alkyl-modified starch, an amine polymer having at least one of a structure represented by the following formula (1) and a structure represented by the following formula (2), and a pigment: The manufacturing method of the inkjet recording paper which does not contain or contains a pigment in 2 mass% or less with respect to the total mass of solid content in the said surface treatment liquid.

(HX in Formula (2) is a mineral acid or an organic acid.) The method for producing an inkjet recording sheet according to claim 8, wherein the base sheet is selected and the coating amount of the surface treatment liquid is adjusted so that the basis weight of the obtained inkjet recording sheet is 16 to 70 g / m ² .   The method for producing an ink jet recording sheet according to claim 8 or 9, wherein the content of the alkyl-modified starch in the surface treatment liquid is 40 to 70 mass% with respect to the total mass of the solid content in the surface treatment liquid.   The inkjet according to any one of claims 8 to 10, wherein the content of the amine polymer in the surface treatment liquid is 30 to 60% by mass with respect to the total mass of the solid content in the surface treatment liquid. Method of manufacturing recording paper.   The method for producing an ink jet recording sheet according to any one of claims 8 to 11, wherein the base paper contains 2 to 35 parts by mass of calcium carbonate based on 100 parts by mass of a pulp solid content.   The ink jet recording paper according to any one of claims 8 to 12, wherein the base paper contains a neutral sizing agent consisting of at least one selected from the group consisting of alkenyl succinic anhydride and alkyl ketene dimer. Method.   The method for producing an inkjet recording sheet according to claim 13, wherein the content of the neutral sizing agent in the base paper is 0.1 to 1.0 parts by mass with respect to 100 parts by mass of the pulp solid content. The coating amount according to any one of claims 8 to 14, wherein, in the coating step, the coating amount of the surface treatment liquid is 0.3 to 2.3 g / m ^{2 in} terms of solid content per one surface of the base paper. Of ink jet recording paper.