KR20180067526A - Evaluation method of coated paper, coated substrate, and ink drying property - Google Patents

Abstract

It is an object of the present invention to provide a coated paper excellent in paper sorting property, a coated substrate excellent in dryness of ink, and a method for accurately evaluating ink dryness. The first problem is solved by a printing paper for printing having a dynamic friction coefficient larger than a static friction coefficient in static friction coefficient and dynamic friction coefficient measured in accordance with JIS-P8142 of less than 30% and according to ISO 15359 . The second problem is solved by a coated substrate having a sheet base and a pigment coating layer provided thereon and having a pore volume (V) of 0.04 cm < ³ > / g or more by the nitrogen adsorption method of the pigment coating layer. The third problem is solved by a method including a step of measuring the pore volume (V) or the average pore diameter (m) of the pigment coating layer by a nitrogen adsorption method.

Description

Evaluation method of coated paper, coated substrate, and ink drying property

The present invention relates to a coated paper, a coated substrate, a method for producing the same, and a method for evaluating ink drying property. More particularly, the present invention relates to a coated paper for mat printing and a method of manufacturing the same.

A coated substrate having a coated layer on a sheet-like substrate is used for various purposes including printing. Among coated base materials, coated base paper (base paper) is particularly important in industry.

Porcelain papers are roughly classified into glossy papers and matte papers. The glossy coated papers include art paper, super art paper, coated papers used for catalogs and brochures, and the like, which have been used in high-grade printing in the past. A matte-coated paper is a blank paper with a lower gloss or print gloss than a glossy paper, a dull coarse paper, and a matte paper. In particular, a matte coated paper has a larger difference between white glossy and printing glossy than a glossy coated paper, and the letter portion after printing is easy to read. As a method for producing the matte tinted paper, there are a method of using a pigment having a large particle diameter as a coating pigment and a method of increasing the unevenness of the surface of the paper by not carrying out the calendering treatment after coating the pigment.

On the other hand, since the surface roughness of the matte coated paper is larger than that of the glossy coated paper, the ink that has reached the surface of the paper tends to penetrate. Therefore, in order to increase the printing density, it is necessary to transfer the ink more abundantly. Therefore, the amount of transfer of the ink is increased in the matte prepreg site, so that the drying tendency is lowered. If the dryness of the ink is inferior, a problem of " rear bury " in which the ink is transferred to the other when the prints after printing are overlapped is likely to occur. Therefore, in general, measures are taken such as using powder of starch or the like to prevent the printed matter from adhering to the paper, or keeping the paper from rubbing after overlapping. Particularly, in the case of performing the double-side printing, if the "backside" occurs, the printed image is damaged and the value of the printed matter is considerably impaired, so that the standing time after the single side printing is made long, It is necessary to dry the ink until it is no longer necessary. If the dryness of the ink is inferior, the settling time is prolonged, and the working efficiency is lowered. Further, in the double-sided printing, the printed image on the surface already printed by the roll or the like is rubbed when printing is performed on the opposite surface, so that if the drying of the ink is poor, the printed image may be damaged. Therefore, in order to improve the printing speed and to cope with double-sided printing, performance in which the ink is dried quickly is required.

It has also been studied to adjust the coefficient of friction of paper in order to avoid problems such as difficulty in setting the paper on the printing machine due to the fact that the paper easily slips and the paper is not aligned on the coated paper or difficulties in cutting. Generally, in paper, it is known that the dynamic friction coefficient becomes smaller than the static friction coefficient. Therefore, when the static friction coefficient is increased to some extent, a suitably high dynamic friction coefficient is obtained, and therefore, the prior art has focused on adjusting the static friction coefficient. Although there is a technique that focuses on the relationship between the dynamic friction coefficient and the static friction coefficient (for example, Patent Document 1), the technique also assumes that the dynamic friction coefficient is smaller than the static friction coefficient.

As described above, the matched prepregs are required to have quick drying properties particularly in the ink drying, but the demand for quick drying properties of the coated papers has increased from recent printing situations. Specifically, in the field of sheet laminating, the tendency of small lot printing and short lead time is becoming strong. In the printing press, H-UV printing (hybrid UV printing) is adopted, and in ink, And the movement toward quick-drying, such as ink being put into the market, is increasing.

The absorption of the solvent component in the ink into the coating layer is determined by the material of the coating layer, the coating layer structure, the printing conditions, the ink conditions and the like. For this reason, there has heretofore been known a method for improving the absorption and felling performance and ink dryness by blending satin white on the coated layer to improve the dryness of the ink and maintaining a constant void volume in the coated layer (Patent Document 2) , A method using an ink excellent in drying and contamination resistance (Patent Document 3), and so forth. There have also been many studies focused on the coating layer structure.

Development of a coated paper having excellent ink drying property requires an accurate evaluation method of ink fast drying property. Regarding the relationship between the pigment coating layer and the solvent absorbency, Lucas-Washburn's formula shown in the expression (1) in which a large number of fine holes existing in the pigment coating layer are regarded as an aggregate of capillaries is widely used. Where L is the penetration depth of the solvent, r is the average radius of the capillary, t is the time, γ is the surface tension of the solvent, θ is the contact angle of the capillary wall with the solvent, and η is the viscosity of the solvent. And, assuming that the pore structure of the pigment coating layer is arranged with n circular tubes having an average radius r, the ink solvent penetration amount (v) into the pigment coating layer is represented by the formula (2) Can be modified as shown in equation (3). d is the thickness of the pigment coating layer, V is the pore volume of the pigment coating layer, and k is the viscosity of the ink. That is, the larger the pore diameter and pore volume in the pigment coating layer, and the smaller the coating thickness of the pigment coating layer, the greater the amount of solvent penetration per a certain period of time, thereby improving the ink fast drying property.

As a method for quantitatively evaluating the pore structure of paper, a mercury pressing method is widely used (Patent Document 4), but since mercury is a toxic substance and requires careful handling, In consideration, recently, the number of companies or organizations that restrict use has increased.

Japanese Patent Application Laid-Open No. 08-060597 Japanese Patent Application Laid-Open No. 11-247097 Japanese Unexamined Patent Application Publication No. 2015-063667 Japanese Unexamined Patent Application Publication No. 2014-237898

In view of the above, it is an object of the present invention to provide a coated paper excellent in paper sorting property, a coated substrate having ink drying property, in particular, a matte printing paper, and a method for more accurately evaluating ink drying.

The above-mentioned problems are solved by the following invention.

(1) the white paper gloss according to JIS-P8142 is less than 30%, and

A coated article having a dynamic coefficient of friction greater than a static coefficient of friction in static and dynamic coefficients of friction measured in accordance with ISO 15359.

(2) a pigment, and a pigment coating layer comprising a pigment and an adhesive provided thereon,

Wherein the pigment comprises kaolin or clay,

The coated paper of (1), wherein the adhesive comprises 20 to 50% by weight of latex in the total adhesive.

(3) A coated paper for printing, as described in (1) or (2).

(4) JAPAN TAPPI Paper Pulp Test Method No. The coated paper according to (3), wherein the printing ink has an acceptability of 20 to 35,

(5) A process for coating a pigment coating liquid containing a pigment and an adhesive on a base paper,

Wherein the pigment comprises kaolin or clay,

The process for producing a coated paper according to any one of (1) to (4), wherein the adhesive comprises 20 to 50% by weight of latex in the whole adhesive.

(6) A coated substrate having a sheet-like substrate and a pigment coating layer provided thereon, wherein the pigment coating layer has a pore volume (V) of 0.04 cm ³ / g or more as measured by a nitrogen adsorption method.

(7) The coated substrate according to (6), wherein an average pore diameter (m) of the pigment coating layer by nitrogen adsorption method is 30 nm or more.

(8) The coated substrate according to (6) or (7), wherein the pore volume (V) is 0.09 cm ³ / g or less.

(9) The coated substrate according to any one of (6) to (8), wherein the average pore diameter (m) is 60 nm or less.

(10) The outermost layer of the coated base material is a pigment coating layer. The static friction coefficient and the dynamic friction coefficient of the outermost pigment coating layer side measured in accordance with ISO 15359 are such that the dynamic friction coefficient is larger than the static friction coefficient, (6) to (9).

(11) The coated substrate according to (10), wherein the outermost pigment coating layer contains 25 to 75% by weight of calcium carbonate in the whole pigment.

(12) The coated substrate according to (11), wherein the calcium carbonate is heavy calcium carbonate.

(13) The coated substrate according to (11), wherein the calcium carbonate is a light calcium carbonate.

(14) The coated substrate described in any one of (10) to (13), wherein the outermost pigment coating layer contains 20 to 50% by weight of kaolin or clay in the whole pigment.

(15) The coated substrate according to any one of (10) to (14), wherein the outermost pigment coating layer contains an adhesive and contains 20 to 80% by weight of latex in the adhesive.

(16) The total pore volume (cm ³ / m ² ) defined by the pore volume (V) (cm ³ / g) × the coating amount (c) (g / m ² ) of the pigment coating layer is 0.55 to 4.50 cm ³ / m < ² >, and the coating material described in any one of (6) to (15).

(17) A coated substrate according to any one of (6) to (16), wherein the gloss according to JIS-P8142 is less than 35%.

(18) JAPAN TAPPI Paper Pulp Test Method No. (6) to (17), wherein the coating ink has a printing ink receptivity of 20 to 35 as measured in accordance with the following formula (1).

(19) A coated substrate as described in any one of (6) to (18) which is a coated substrate.

(20) a step of measuring a pore volume (V) or an average pore diameter (m) of the pigment coating layer in a coated substrate having a sheet-like substrate and a pigment coating layer provided thereon by a nitrogen adsorption method; and

And the ink drying property is also increased as V or m is increased.

(21) a step of measuring a coating amount (c) of the pigment coating layer,

And the step of evaluating ink dryness based on the relationship that the larger the V / c or m / c is, the higher the ink drying property is.

According to the present invention, it is possible to provide a coated paper excellent in paper sorting property, a coated substrate having ink drying property, in particular, a matte printing paper, and a method for accurately evaluating ink drying.

Fig. 1 shows the correlation between the ink fast drying property and the pore volume.
Fig. 2 shows the correlation between the ink fast drying property and the average pore diameter.

The present invention includes the following aspects.

First Coated Paper: Coated paper having a dynamic friction coefficient higher than the static coefficient of friction

Second coating base material: A coated base material having a pigment coating layer having a specific pore volume, in particular,

- Evaluation method of ink drying property

Hereinafter, the present invention will be described in detail. In the present invention, " ~ " includes the end value. That is, " X to Y " includes values of X and Y. [ In addition, " X or Y " means any one of X and Y, or both.

I. First Coated Paper

1. Coated paper

The coated paper is a paper having a coated layer such as a clear coated layer and a pigment coated layer on a base paper. The first coated paper of the present invention has a dynamic friction coefficient greater than a static friction coefficient in a static friction coefficient and dynamic friction coefficient measured according to JIS-P8142 of less than 30% and in accordance with ISO 15359. Thereby having excellent paper sortability. The first coated paper of the present invention is preferably a printing coated paper. The printing paper for printing is a paper used by carrying out commercial printing on a surface of a paper on which a pigment coating layer is formed by a printing method such as offset printing, gravure printing, on-demand printing (laser system, inkjet system, electrophotographic system, etc.).

The application of the first coated paper may be various kinds of printing paper such as shear paper, book paper, paper cover paper, newsprint paper, various copy paper, various inkjet printing paper, thermal paper, pressure sensitive paper, kraft paper, Paperboard, paperboard, cardboard, bamboo paper, color paper, water-based paper, fancy paper, wallpaper, fiberboard, photo paper, impregnating paper, deodorant paper, printed electronics, paper, tape paper, envelope paper, cosmetic paper, battery separator, ODP paper, various sanitary paper, cigarette paper, cup paper, abrasive paper, synthetic paper and the like. Among them, the first coated paper of the present invention is suitable as a printing paper provided in various printing methods such as offset printing and gravure printing.

Hereinafter, a first coated paper (also referred to as " first coated paper for printing ") is described as an example of a coated paper for printing.

(1) Blank glossiness

The white paper glossiness is an index indicating the degree of the matte group and is measured according to JIS-P8142 in the present invention. The white glossy gloss of the first printing coated paper of the present invention is preferably less than 35%, more preferably less than 30%. The lower limit of the white paper gloss is not limited, but is preferably 15% or more.

(2) printing ink repairability

The print ink receptivity is an index showing the easiness of drying of ink, and in the present invention, it is an indicator of paper dry pulp test method No. JAPAN TAPPI. 46. Specifically, the printing ink water resistance is evaluated by the difference in whiteness before and after applying the ink by wiping off the ink after a certain amount of ink is applied to paper and after a predetermined time has elapsed. The higher the value, the better the dryness of the ink. In the first printing paper for printing of the present invention, the printing ink receptivity is preferably 20 or more, more preferably 21 or more, and even more preferably 22 or more. The printing ink receptivity is preferably 35 or less, more preferably 31 or less, more preferably 30 or less, and still more preferably 25 or less. On the other hand, when the printing ink receptivity is more than 35, the dryness of the ink is excessive and the printing gloss is lowered.

(3) Coefficient of Friction

When the coated paper for printing slides excessively in the printing machine, printing defects occur. However, the inventors found that this problem can not be solved only by increasing the static friction coefficient, and that the printing paper for mat printing has a particularly high tendency did. The inventors have found that the problem in the static state and the problem in the dynamic state can be solved by giving the dynamic friction coefficient higher than the static friction coefficient to the printing paper for printing.

The first printing paper for printing according to the present invention has a dynamic friction coefficient larger than a static friction coefficient. The coefficient of friction is measured in accordance with ISO 15359. In ISO 15359, the static friction coefficient and the dynamic friction coefficient are measured three times using the same sample, the first and third values are adopted for the static friction coefficient, and the third value is adopted for the dynamic friction coefficient . In the present invention, the first value is adopted for the static friction coefficient. Although it is not limited, it is preferable that the rate of increase calculated from [(dynamic friction coefficient) - (static friction coefficient)] / (static friction coefficient) is 2 to 25%, more preferably 3 to 20%. The specific coefficient of friction is not limited, but the coefficient of static friction is preferably 0.3 to 0.7, more preferably 0.4 to 0.6. When the coefficient of friction is in this range, problems before the printing and problems within the printing machine are solved.

(4) Pore volume (V)

The first printing paper for printing of the present invention preferably has a pore volume (V) of 0.04 cm < ³ > / g or more. Having a pore volume (V) in this range is good for ink drying. The pore volume (V) is determined by the nitrogen adsorption method. The pore volume (V) is more preferably 0.045 cm < ³ > / g or more. A pore volume (V) is more preferably 0.09cm ³ / g or less preferred, and 0.085cm ³ / g or less, more preferably 0.08cm ³ / g or less. Specifically, in the present invention, the pore volume is obtained from a desorption isotherm obtained by a nitrogen adsorption method. For measurement and analysis, Tristter 3000 manufactured by Shimadzu Corporation can be used. In the present application, the pore volume obtained by the Tristter 3000 is regarded as the pore volume of the pigment coating layer.

Since the pigment coating layer is formed on the base paper, the pore volume (V) of the pigment coating layer can be measured by peeling the base coating layer and the pigment coating layer. Alternatively, the pore volume of the laminate including the base layer and the pigment coating layer is measured, and the value of the obtained pore volume is converted into the value per unit coating amount from the weight ratio of the base paper and the pigment coating layer to obtain the pore volume of the pigment coating layer ) Can be obtained. In the present invention, the latter method is preferable. As a method for measuring the coating amount of the pigment coating layer, for example, the method described in Japanese Patent No. 5827187 can be mentioned.

(5) Total pore volume

A total pore volume (cm ³ / m ²⁾ has a pore volume ^{(V) (cm 3 / g} ) × a coated amount of (c) is defined by a (g / m ^2), the value of 0.55cm ³ / m ² or more it is preferred, 0.60cm ³ / m ² or more and more preferably, 0.65cm ³ / m ² or more is more preferable. The upper limit of the total pore volume, 4.50cm ³ / m ² or less are preferred, 3.60cm ³ / m ² or less are more preferable and, 2.70cm ³ / m ² is more preferably less.

(6) Average pore diameter (m)

The average pore diameter (m) is determined by the method described above. From the viewpoint of ink drying property, the average pore diameter (m) is preferably 30 nm or more. The upper limit of the average pore diameter (m) is preferably 60 nm or less. Specifically, in the present invention, the average pore diameter is obtained from a desorption isotherm obtained by a nitrogen adsorption method. In the present application, the average pore diameter obtained by the tristter 3000 is regarded as the average pore diameter of the pigment coating layer.

(7) Origin

1) Pulp

A known paper pulp such as chemical pulp, mechanical pulp, phage pulp can be used for the paper, but it is preferable to use chemical pulp. Examples of the chemical pulp include those produced by the kraft pulping method, those produced by the sulfite pulping method, the bleached chemical pulp and the unbleached chemical pulp. In the present invention, they can be used. However, the chemical pulp produced by the Kraft process Pulp is preferable in terms of production cost and quality. The content of chemical pulp in the raw pulp is preferably 60% by weight or more, more preferably 80% by weight or more, still more preferably 90% by weight or more, and particularly preferably 95% by weight or more in terms of whiteness and the like Do.

2) Fee (charge)

It is possible to use the transfer fee of the public on the ground. Examples of the known charge include heavy calcium carbonate, light calcium carbonate, clay, silica, light calcium carbonate-silica composite, kaolin, calcined kaolin, delaminated kaolin, white carbon, talc, magnesium carbonate, barium carbonate, , Amorphous silica produced by neutralization with a mineral acid such as aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, zinc oxide, titanium oxide and sodium silicate; an inorganic powder such as urea-formalin resin, melamine resin, polystyrene resin, Phenol resin, and the like. Among them, heavy calcium carbonate and light calcium carbonate, which are typical transfer materials in paper making and alkali grass, are preferably used for improving opacity. The charge rate in the paper is not particularly limited, but is preferably 1 to 40% by weight, more preferably 10 to 35% by weight.

3) Others

Known paper additives can also be used. For example, if necessary, additives such as sulfuric acid bands and various anionic, cationic, nonionic or positive yield enhancers, freeness enhancers, various strength enhancers, and internal sizing agents may be added as needed Can be used. Examples of the dry strength agent include polyacrylamide and cationized starch. Examples of the wet strength agent include polyamidoamine epichlorohydrin and the like. These medicines are added in such a range that there is no influence of lipid or workability. Examples of the internal sizing agent include alkylketene dimer, alkenylsuccinic anhydride, and rosin sizing agent. In addition, dyes, color pigments, fluorescent whitening agents, pH adjusting agents, antifoaming agents, pitch control agents, slime control agents and the like can be added as needed.

4) Basis weight of raw paper

The first basis weight of the base paper of the coated printing paper of the present invention is 40 ~ 160g / m ² is preferable, and, 45 ~ 150g / m ² are more preferred, and, 50 ~ 130g / m ² is more preferred, but is not limited to these. In addition, the substrate of the present invention may contribute to the single layer surfacing multi-layer deposition, but the single layer deposition is preferable.

(8) Pigment Coating Layer

1) Pigment

The pigment coating layer is a coating layer containing a pigment. The pigment coating layer may be a single layer or two or more layers.

In the present invention, a known pigment can be used. Examples thereof include inorganic pigments such as kaolin, clay, engineered kaolin, distillate clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicate, colloidal silica, And an organic pigment such as a hollow-room type, hollow-type, or core-shell type. A plurality of these pigments may be used in combination.

In order to achieve the above properties, it is preferable to use calcium carbonate, kaolin, or clay. The total amount of the pigment is preferably 20 parts by weight or more and less than 50 parts by weight, more preferably 20 to 48 parts by weight, and still more preferably 30 to 47 parts by weight, per 100 parts by weight of the pigment. As the calcium carbonate, calcium carbonate such as heavy calcium carbonate and light calcium carbonate is preferable. As the hard calcium carbonate, a hard calcium carbonate (causticized hard calcium carbonate) produced by a causticizing step of a pulp manufacturing process described in Japanese Patent No. 5274077 may be used.

As the pigment, it is preferable to use a pigment having a particle diameter of 2 탆 or less of 80% or more when the particle size distribution is measured by a sedimentation method. The ratio is more preferably 85% or more, and more preferably 90% or more. The particle size distribution of the pigment by the sedimentation method can be measured by Shimadzu Corporation, Sedigraph 5100 and the like.

2) Adhesive

The pigment coating layer includes an adhesive (binder) as a matrix. The adhesive is not limited, and a known adhesive may be used. Examples of the adhesive include various copolymers such as styrene · butadiene, styrene · acrylic, ethylene · vinyl acetate, butadiene · methyl methacrylate, and vinyl acetate · butyl acrylate, a maleic anhydride copolymer, acrylic acid · methyl methacrylate Latex such as a copolymer based on a copolymer; Polyvinyl alcohols such as saponification polyvinyl alcohol, partially-effect polyvinyl alcohol, carboxy-modified polyvinyl alcohol, and acetacetyl-modified polyvinyl alcohol; Proteins such as casein, soybean protein, and synthetic protein; Starches such as oxidized starch, amphoteric starch, urea phosphoric acid esterified starch, hydroxyethyl etherified starch, and dextrin; Cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, hydroxymethylcellulose and the like. These plural species can be used in combination.

The amount of the adhesive is preferably 5 to 20 parts by weight, more preferably 8 to 16 parts by weight, based on 100 parts by weight of the pigment, from the viewpoints of printing suitability and coating suitability. When the total amount of the adhesive is more than 20 parts by weight, the viscosity of the pigment coating solution becomes high, so that a fishing trouble is likely to occur at the time of coating. In addition, the drying tendency of the ink tends to be lowered. On the other hand, if the total amount of the adhesive is less than 5 parts by weight, it becomes difficult to obtain sufficient surface strength.

In order to achieve the above properties, it is preferable that 20 to 55% by weight of latex is included in the whole adhesive, and it is preferable that latex is included in the range of 25 to 45% by weight. When two or more pigment coating layers are provided, it is preferable that the outermost pigment coating layer farthest from the base paper contains 20 to 80% by weight of latex as a whole adhesive, and 25 to 75% by weight of latex More preferably 25 to 55% by weight of latex. As other adhesives, it is particularly preferable to use all kinds of starches, especially oxidized starch. The reason why the pre-sorting is preferable is that, as compared with the latex, the pre-sorting is more likely to cause penetration of the coating solution into the raw paper because the water retention property of the pigment coating solution is high, . In other words, when the former classification is used, the coverage of the paper by the pigment coating layer becomes better. As a result, it is expected that the printing quality, particularly the printing glossiness, and the ink drying property are improved.

3) Others

The pigment coating layer may contain a dispersing agent, a thickening agent, a repairing agent, a defoaming agent, a water-proofing agent, and various auxiliaries incorporated in conventional pigments for coated paper, if necessary.

2. Manufacturing Method

The first coating layer for printing of the present invention can be produced by a known method, but it is preferable that the coating layer is prepared by coating a pigment coating liquid containing a pigment and an adhesive on a base paper with a blade.

(1) Preparation of paper

As for the paper, it is already described. The raw paper is produced by a known paper making method.

For example, it can be carried out by using a long paper machine including a top wire, a hot top former, a gap former, a circular net paper machine, a cardboard machine using a pan paper machine and a Yankee dryer machine, etc. . The pH at the time of papermaking may be acidic, neutral or alkaline, but it is preferably neutral or alkaline. The papermaking speed is also not particularly limited.

(2) Smoothing processing of paper

Before applying the pigment coating liquid to the obtained raw paper, it is preferable that the raw paper is subjected to a smoothing treatment by various calendering apparatuses. As such a calender device, a calender device generally used such as a super calender or a soft calender can be suitably used. Calendering conditions include temperature of the rigid roll, calender pressure, number of nips, roll speed, paper moisture before calendering, and the like, are appropriately selected according to the required quality.

(3) Preparation of pigment coating liquid

The pigment coating liquid can be prepared by dispersing or dissolving pigments, adhesives and, if necessary, additives in water. The composition of each component is adjusted so that the above-described pigment coating layer can be formed. When the coating of the blade is carried out, the solid content concentration of the pigment coating liquid is preferably from 40 to 70% by weight, and more preferably from 60 to 70% by weight. It is preferable that the viscosity of the pigment coating solution is in the range of 500 to 3000 mPa · s, the B-type viscosity measured at 60 rpm at room temperature.

(4) Coating method

The coating method is not limited, and known coating machines such as roll coater and blade coater can be used. The coating speed is not particularly limited, but is preferably 400 to 1800 m / min for a blade coater and 400 to 2000 m / min for a roll coater. In the present invention, the pigment coating layer may be coated with a single-layer blade coater, coated with a roller coater, coated with a blade coater, coated with a blade coater and then coated with a blade coater, It is preferable to use a blade coater.

The pigment coating layer may be provided in one layer or in plural layers. Further, a clear coating layer may be provided on the base paper, and a pigment coating layer may be provided thereon.

Coating amount of the pigment coating layer of the present invention (g / m ²⁾ is, on one side more than the solid content to 2g / m ² per (片面) are preferred, 5g / m ² or more, and more preferably, 10g / m ² or more Is more preferable. When the coating amount is less than 5 g / m ² , the irregularities on the surface of the paper substrate can not be sufficiently covered, and thus the printability of the printing ink is remarkably lowered. On the other hand, a coated amount of the pigment coating layer, 50g / m ² or less is preferable, and, 40g / m ² or less, and more preferably, 35g / m ² is more preferably less.

The basis weight of the first printing coated paper of the present invention is not particularly limited, but is about 50 g / m ² or more and about 260 g / m ² or less.

(5) Other processes

The method of drying the coated layer in a wet state is not limited, and for example, a steam heating cylinder, a heated hot air dryer, a gas heater dryer, an electric heater dryer, an infrared heater dryer and the like can be used.

The first printing coated paper of the present invention may be subjected to a smoothing treatment by various calenders after drying the coated layer in the wet state. As such a calender device, a calender device generally used such as a super calender or a soft calender can be suitably used. Calendering conditions include the temperature of the rigid roll, the calender pressure, the number of nips, the roll speed, the water content of the paper before the calendering, and the like, depending on the desired quality.

II. The second coating material substrate

The coating material field is a substrate having a pigment coating layer on a sheet-like substrate. Sheet-like base member refers to a member having a large width and a length with respect to the thickness, and examples thereof include paper, polymer sheet, metal foil, nonwoven fabric, plate, cloth, glass plate, tile and fiber plate. In the present invention, the film and the sheet have the same meaning. Specific examples of the application of the second coated base material include various kinds of printing paper such as shear paper, book paper, paper cover paper, newspaper paper, various copy paper, various inkjet printing paper, thermal paper, , Kraft paper, pressed paper, packaging paper, paper container paper, cardboard, bamboo paper, color paper, water paper, fancy paper, wallpaper, photo paper, impregnated paper, , Tape paper, envelope paper, cosmetic paper, battery separator, ODP paper, various sanitary paper, cigarette paper, cup paper, abrasive paper, and synthetic paper. Other uses include building materials, adsorbents, shield materials, coating materials for various uses, and the like, but the present invention is not limited thereto. In the present invention, it is preferable that paper (paper) is used as the substrate, that is, the coated substrate is a coated paper. Among the coated paper, the coated paper for printing is preferable as described above, and the coated paper for mat printing is particularly preferable.

Hereinafter, for the sake of simplicity, the second coated base material (hereinafter also referred to as " second printing-use coated paper ") will be described taking the coated paper for matte printing as an example.

When a pigment having a large particle size is used as a coating pigment, the larger the particle diameter of the pigment, the smaller the pore volume of the pigment coating layer and the lower the ink drying property. The second printing coated paper of the present invention solves this problem.

1. Printing paper

The second printing coated paper of the present invention comprises paper and a pigment coating layer provided thereon, and the pore volume (V) of the pigment coating layer according to the nitrogen adsorption method is not less than 0.04 cm ³ / g. The white paper glossiness of the coated paper for printing according to JIS-P8142 was less than 35%, and the paper glossiness of the coated paper for printing was measured by JAPAN TAPPI paper pulp test method No. 1. 46 is preferably in the range of 20-35. The second coated paper for printing of the present invention is subjected to commercial printing by a printing method such as offset printing, gravure printing, on-demand printing (laser method, ink jet method, electrophotographic method, etc.) on the surface of the paper provided with the pigment coating layer Refers to the paper used.

(1) Pore volume (V)

The pore volume (V) is determined by the nitrogen adsorption method. The second printing paper for printing according to the present invention has excellent pore volume (V) of 0.04 cm < ³ > / g or more and, therefore, excellent ink drying property. The pore volume (V) is more preferably 0.045 cm < ³ > / g or more. A pore volume (V) is more preferably 0.09cm ³ / g or less preferred, and 0.085cm ³ / g or less, more preferably 0.08cm ³ / g or less. Specifically, in the present invention, the pore volume is obtained from a desorption isotherm obtained by a nitrogen adsorption method. For measurement and analysis, Tristter 3000 manufactured by Shimadzu Corporation can be used. In the present invention, the pore volume obtained by the triester 3000 is regarded as the pore volume of the pigment coating layer.

Since the pigment coating layer is formed on the base paper, the pore volume (V) of the pigment coating layer can be measured by peeling the base coating layer and the pigment coating layer. Alternatively, the pore volume of the laminate including the base layer and the pigment coating layer is measured, and the value of the obtained pore volume is converted into the value per unit coating amount from the weight ratio of the base paper and the pigment coating layer to obtain the pore volume of the pigment coating layer ) Can be obtained. In the present invention, the latter method is preferable. As a method for measuring the coating amount of the pigment coating layer, for example, the method described in Japanese Patent No. 5827187 can be mentioned.

(2) Total pore volume

A total pore volume (cm ³ / m ²⁾ has a pore volume ^{(V) (cm 3 / g} ) × a coated amount of (c) is defined by a (g / m ^2), the value of 0.55cm ³ / m ² or more it is preferred, 0.60cm ³ / m ² or more and more preferably, 0.65cm ³ / m ² or more is more preferable. The upper limit of the total pore volume, 4.50cm ³ / m ² or less are preferred, 3.60cm ³ / m ² or less are more preferable and, 2.70cm ³ / m ² is more preferably less.

(3) Average pore diameter (m)

The average pore diameter (m) is determined by a nitrogen adsorption method. From the viewpoint of ink drying property, the average pore diameter (m) is preferably 30 nm or more. The upper limit of the average pore diameter (m) is preferably 60 nm or less. Specifically, in the present invention, the average pore diameter is obtained from a desorption isotherm obtained by a nitrogen adsorption method. In the present invention, the average pore diameter obtained by the Tristter 3000 is regarded as the average pore diameter of the pigment coating layer.

(4) Blank glossiness

The white paper glossiness is an index showing the degree of gloss in white paper, and is measured according to JIS-P8142 in the present invention. As described above, since the coated paper for printing of the present invention is a coated paper for printing in a matte having a large difference between white glossy and printing glossy, the white glossy degree is preferably less than 35% and more preferably less than 30%. The lower limit of the white paper gloss is not limited, but is preferably 15% or more.

(5) printing ink hydraulic properties

The printing ink water fastness is measured as described for the first printing paper. In the second printing paper for printing of the present invention, the printing ink receptivity is 20 or more, preferably 21 or more, and more preferably 22 or more. The printing ink receptivity is 35 or less, preferably 33 or less, more preferably 31 or less, and further preferably 30 or less. If the print ink has a water solubility of less than 20, the dryness of the ink is not sufficient. On the other hand, when the printing ink receptivity is more than 35, the dryness of the ink is excessive and the printing gloss is lowered.

(6) Coefficient of Friction

The second printing paper for printing according to the present invention preferably has a dynamic friction coefficient larger than a static friction coefficient. There is a case in which a problem arises in the coated paper for printing that the paper easily slips and the paper is not aligned and the setting on the printing machine becomes difficult or the cutting becomes difficult. However, there is a problem that a point having a dynamic friction coefficient larger than the static friction coefficient This problem can be solved in. Conventionally, in order to avoid the problem, it has been examined to adjust the paper friction coefficient. Generally, in paper, it is known that the dynamic friction coefficient becomes smaller than the static friction coefficient. Therefore, when the static friction coefficient is increased to some extent, a suitably high dynamic friction coefficient is obtained, and therefore, the prior art has focused on adjusting the static friction coefficient. Although there is a technique which focuses on the relationship between the dynamic friction coefficient and the static friction coefficient (for example, Japanese Unexamined Patent Application Publication No. 08-060597), this technique also assumes that the dynamic friction coefficient is smaller than the static friction coefficient. However, in the present invention, the above problem can be solved by a different idea from the conventional thinking method.

The coefficient of friction is measured as described for the first printing paper. Although it is not limited, it is preferable that the rate of increase calculated from [(dynamic friction coefficient) - (static friction coefficient)] / (static friction coefficient) is 2 to 25%, more preferably 3 to 20%. The specific coefficient of friction is not limited, but the coefficient of static friction is preferably 0.3 to 0.7, more preferably 0.4 to 0.6. When the coefficient of friction is in this range, problems before the printing and problems within the printing machine are solved.

(7) Origin

1) Pulp

The pulp is as described for the first printing paper.

2) charge

As for the transfer, the same as described in the first printing paper. Among them, when a heavy calcium carbonate or a light calcium carbonate, which is a typical charge in neutral glue or alkali grass, is used, a high opacity improving effect is obtained. As the hard calcium carbonate, a hard calcium carbonate (causticized hard calcium carbonate) produced by a causticizing step of pulp manufacturing process described in Japanese Patent No. 5274077 may be used. The charge rate in the paper is not particularly limited, but is preferably 1 to 40% by weight, more preferably 10 to 35% by weight.

3) Others

In the present invention, known paper additives can also be used. The additive is as described for the first printing paper.

4) Basis weight of raw paper

The basis weight of the raw paper is as described in the first printing paper.

(8) Pigment Coating Layer

1) Pigment

In the present invention, a known pigment can be used. Examples thereof include inorganic pigments such as kaolin, clay, engineered kaolin, distillate clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicate, colloidal silica, And organic pigments such as a hollow-room-type, hollow-type, or core-shell type. A plurality of these pigments may be used in combination. As hard calcium carbonate, hardened hard calcium carbonate may be used.

In the present invention, it is preferable to use calcium carbonate, kaolin, or clay as the pigment in order to achieve the above-mentioned blank glossiness, printing ink water-repellency, friction coefficient and the like. Particularly, in order to achieve the friction coefficient, it is preferable that the outermost layer of the coated paper for printing is a pigment coating layer, and that the outermost pigment coating layer contains calcium carbonate in an amount of 25 to 75% by weight in the whole pigment. Although not limited to other pigments, it is preferable to contain kaolin or clay in an amount of 20 to 50% by weight in the total pigment of the outermost pigment coating layer. However, the total amount of calcium carbonate and kaolin or clay is adjusted so as not to exceed 100% by weight of the total pigment. The calcium carbonate is preferably heavy calcium carbonate or light calcium carbonate. The hard calcium carbonate is more preferably a hardened hard calcium carbonate.

In the present invention, the pore volume (V) and the average pore diameter (m) can be easily achieved by adjusting the average particle size of the pigment. Specifically, for example, a volume average particle diameter (D50) of 50% by volume of calcium carbonate is preferably 0.5 to 6.0 占 퐉, more preferably 0.5 to 2.0 占 퐉. The volume average particle diameter (D50) of kaolin or clay of 50% volume is preferably 1.0 to 6.0 占 퐉, more preferably 2.0 to 5.5 占 퐉. When the diameter is smaller than 1.0 占 퐉, the white glossy gloss is increased, and it may become difficult to obtain the feel of the matte mat. When the diameter is larger than 6.0 占 퐉, operational troubles such as deterioration of the fluidity of the coating liquid and abrasion of the blade are liable to occur, and ink rub and dryness may be deteriorated at the time of printing. The particle size of these pigments can be measured by a laser diffraction particle size analyzer such as MastersizerS manufactured by Malvern.

2) Adhesive

The pigment coating layer includes an adhesive (binder) as a matrix. The adhesive used in the present invention is not limited, and a known adhesive may be used. Examples of the adhesive include various copolymers such as styrene / butadiene, styrene / acrylic, ethylene / vinyl acetate, butadiene / methyl methacrylate / vinyl acetate / butyl acrylate, Latex copolymers; Polyvinyl alcohols such as fully-effect polyvinyl alcohol, partially-effect polyvinyl alcohol, carboxy-modified polyvinyl alcohol, and acetacetyl-modified polyvinyl alcohol; Proteins such as casein, soybean protein, and synthetic protein; Starches such as oxidized starch, amphoteric starch, urea phosphoric acid esterified starch, hydroxyethyl etherified starch, and dextrin; Cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, hydroxymethylcellulose and the like. These plural species can be used in combination. Preferably, styrene-butadiene copolymer, oxidized starch, dextrin and the like can be given.

In the present invention, as the adhesive for the outermost coat layer, various copolymers such as styrene · butadiene series, styrene · acrylic series, ethylene · vinyl acetate series, butadiene · methyl methacrylate series and vinyl acetate · butyl acrylate series, It is preferable to use a latex such as an acrylic acid-methyl methacrylate-based copolymer, and more preferably a styrene-butadiene-based copolymer. By adjusting the average particle size and the glass transition temperature measured by the dynamic light scattering method of latex, it is easy to obtain high ink dryness in the matte printing printing paper. The preferred average particle diameter of the latex is 70 to 150 nm, and more preferably 70 to 120 nm. When the average particle size is small, the latex migrates during drying, which may interfere with the formation of a uniform pigment coating layer, and irregular growth may occur. In addition, if the average particle size is large, the ink drying property is improved, but since the ink penetrates into the pigment coating layer, the printing gloss may deteriorate. The glass transition temperature of the latex is preferably about -30 ° C to 30 ° C, more preferably -25 ° C to 20 ° C, and more preferably -20 ° C to 15 ° C. When the glass transition temperature is too low, there is a fear that the coating ability of the coating is deteriorated. In addition, when the glass transition temperature is too high, the surface strength of the coated paper is insufficient, and the white glossy gloss becomes excessive, and it becomes difficult to obtain the white glossy gloss of the matte matte required in the present invention.

The amount of the adhesive is preferably 5 to 20 parts by weight, more preferably 8 to 16 parts by weight, based on 100 parts by weight of the pigment, from the viewpoints of printing suitability and coating suitability. When the total amount of the adhesive is more than 20 parts by weight, the viscosity of the pigment coating solution becomes high, so that a fishing trouble is likely to occur at the time of coating. In addition, the drying tendency of the ink tends to be lowered. On the other hand, if the total amount of the adhesive is less than 5 parts by weight, it becomes difficult to obtain sufficient surface strength.

In the present invention, in order to achieve the physical properties described above, it is preferable to include 20 to 80% by weight of latex in the total adhesive of the outermost pigment coating layer, more preferably 25 to 75% by weight of latex, To 50% by weight of latex. As other adhesives, it is preferable to use pre-classified, especially oxidized starch or dextrin. The reason why the pre-classification is preferable is that, as compared with the latex, the pre-classification has a high water-retention property of the pigment coating liquid, so that penetration of the coating liquid into the raw paper is less likely to occur and it can be considered that the pigment coating layer effectively covers the paper. In other words, when the former classification is used, the coverage of the paper by the pigment coating layer becomes better. As a result, it is expected that the printing quality, particularly the printing glossiness, and the ink drying property are improved.

3) Others

The pigment coating layer may contain a dispersing agent, a thickening agent, a repairing agent, a defoaming agent, a water-proofing agent, and various auxiliaries incorporated in conventional pigments for coated paper, if necessary.

3. Manufacturing Method

The second coating layer for printing of the present invention can be produced by a known method. However, it is preferable to apply one or two layers of a pigment coating liquid containing a pigment and an adhesive on a base paper, and the coating method is a roll coater and a blade coater .

(1) Preparation of paper

The preparation of the base paper is the same as described for the first printing paper.

(2) Smoothing processing of paper

The smoothing treatment of the paper is the same as described for the first printing paper.

(3) Preparation of pigment coating liquid

The pigment coating liquid of the present invention can be prepared by dispersing or dissolving pigments, adhesives and, if necessary, additives in water. The composition of each component is adjusted so that the above-described pigment coating layer can be formed. When the coating of the blade is carried out, the solid content concentration of the pigment coating liquid is preferably from 40 to 70% by weight, and more preferably from 60 to 70% by weight. It is preferable that the viscosity of the pigment coating solution is in the range of 500 to 3000 mPa · s, the B-type viscosity measured at 60 rpm at room temperature.

(4) Coating method

The coating method is not limited, and known coating machines such as roll coater and blade coater can be used. The coating speed is not particularly limited, but is preferably 400 to 1800 m / min for a blade coater and 400 to 2000 m / min for a roll coater. In the present invention, the pigment coating layer may be coated with a single-layer blade coater, coated with a roller coater, coated with a blade coater, coated with a blade coater and then coated with a blade coater, It is preferable to use a blade coater.

The pigment coating layer may be provided in one layer or in plural layers. Further, a clear coating layer may be provided on the base paper, and a pigment coating layer may be provided thereon. The outermost layer is preferably a pigment coating layer.

Coating a pigment coating layer of the present invention the amount of ^{(c) (g / m 2} ) is, on a per-sided solid 2g / m ² or more is preferable, and, 5g / m ² or more, and more preferably, 10g / m ² or more Is more preferable. When the coating amount is less than 5 g / m ² , the irregularities on the surface of the paper substrate can not be sufficiently covered, so that the water repellency of the printing ink is remarkably lowered. On the other hand, a coated amount of the pigment coating layer, 50g / m ² or less is preferable, and, 40g / m ² or less, and more preferably, 35g / m ² is more preferably less.

The basis weight of the second printing paper for printing of the present invention is not particularly limited, but is about 50 g / m ² or more and about 260 g / m ² or less.

(5) Other processes

The method of drying the pigment coating layer in a wet state is not limited, and for example, a steam heating cylinder, a heating hot air dryer, a gas heater dryer, an electric heater dryer, an infrared heater dryer and the like can be used.

The second printing coated paper of the present invention may be subjected to a smoothing treatment by various calendaring apparatuses so as not to impair the feel of the matte after drying the wet coated pigment coating layer. As such a calender device, a calender device generally used such as a super calender or a soft calender can be suitably used. As calendar finishing conditions, the temperature of the rigid roll, the calender pressure, the number of nips, the roll speed, the paper moisture before the calendering, and the like are appropriately selected according to the required quality.

III. Evaluation method of ink fast drying property

As a method for quantitatively evaluating the pore structure of a paper, a mercury pressing method is widely used. However, in a mesopore (2 to 50 nm) region which becomes a pore region of a pigment coating layer, There is a possibility that the pores are deformed. The evaluation method of the present invention can solve these problems.

(1) Measurement process of pore structure

The method includes a step of measuring a pore volume (V) or an average pore diameter (m) of the pigment coating layer in a coated substrate having a sheet-like substrate and a pigment coating layer provided thereon by a nitrogen adsorption method do. The nitrogen adsorption method is a method of adsorbing nitrogen molecules on a pigment coating layer to determine the pore volume or the average pore diameter from the behavior of pressure and adsorption amount. As a device capable of measuring the pore structure by the nitrogen adsorption method, a device such as Tristter 3000 manufactured by Shimadzu Corporation can be used.

(2) Evaluation process

As shown by the above-described formula (3), the larger the pore volume (V) or the average pore diameter (m) of the pigment coating layer, the higher the ink penetration speed, that is, the ink drying property. Therefore, based on this relationship, ink drying can be evaluated in the case of evaluating using the same ink in a coated base material having a pigment coating layer of a certain thickness.

As shown by the formula (3), the penetration speed of the ink is also influenced by the coating amount of the pigment coating layer. Therefore, when the coating amount of the pigment coating layer is c, it is also possible to evaluate the coating amount c considering the relationship that the ink drying property becomes higher as V / c or m / c is larger.

By the evaluation method of the present invention, the pore volume (V) or the average pore diameter (m) of the pigment coating layer optimum for developing ink drying can be obtained. The evaluation method of the present invention is preferable for the evaluation of the coated paper in which the substrate is paper (paper).

Example

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. Parts by weight and% by weight are values in terms of solid content.

1. First printing paper

<Evaluation method>

(1) Blank glossiness

It was measured in accordance with JIS-P8142.

(2) printing ink repairability

JAPPAN TAPPI Paper Pulp Test Method No. 46: Paper and paperboard-Printing ink Aqueousity Test Method-The K & N ink method was used. The measurement of whiteness was carried out under the condition including UV light (UV-In).

(3) static friction coefficient and dynamic friction coefficient

It was measured according to ISO 15359. In the case of three repetitive measurements, the first measured value was adopted as the static friction coefficient, and the third measured value was used as the dynamic friction coefficient.

(4) ink drying by sensory evaluation

After printing at a printing speed of 8000 sheets / hr so that the ink deposition density of the non-printing portion becomes 2.00 in ink, using an Offset Sheet Ink (NEX-M, available from Toyo Ink) with an offset sheetfed press (four colors) , The mucilage printing section was touched with the fingertip every 10 minutes from immediately after the printing, and the degree of the drying speed of the ink was sensed. If the evaluation is 4 or 3, there is no practical problem.

4: Very good

3: Good

2: slightly behind

1: falling

(5) ink rub

The ink was printed so as to have an ink thickness of 1.80 at the printing speed of 8000 sheets / hr and offset printing ink (NEX-M, available from Toyo Ink Co., Ltd.) using Offset Sheet Laminator (four colors) , And the sample was rubbed and rubbed once by applying a load of 500 gf so that the mucin printing portion joined to the white paper portion by a judge type friction rubfastness tester and the ink transferred to the white paper portion was visually evaluated as ink rub. If the evaluation is 4 or 3, there is no practical problem.

4: Very good

3: Good

2: slightly behind

1: falling

(6) Uneven dot

The ink deposition density of the printing area at the printing speed of 8,000 sheets / hr was 1.60 in the indigo ink (NIA-M manufactured by Toyo Ink Co., Ltd.) using an offset sheet-fed printing press (four colors) (CM) so as to be 1.50 (red). The irregularity in the growth of Na-Hong (CM) halftone (50%) printed portion of the obtained print was visually evaluated. If the evaluation is 4 or 3, there is no practical problem.

4: Very good

3: Good

2: slightly behind

1: falling

(7) Printing gloss (gloss difference)

(NEX-M manufactured by Toyo Ink Co., Ltd.) with an offset sheet-fed press (four colors) manufactured by Roland Co., Ltd. so that the ink-ink concentration of the printing portion at the printing speed of 8,000 sheets / (CM). The glossiness of the Nam Hong (CM) solid printed portion of the obtained prints was measured according to JIS P-8142.

If the difference in glossiness from the printing glossiness to the glossiness in the glossiness is 20 or more, preferably 25 or more, a difference in gloss between the printing portion and the white paper portion is sufficiently obtained, and there is no practical problem.

Gloss level difference (%) = Print gloss (%) - Blank gloss (%)

(8) Printability (paper alignment)

500 copies were printed using an offset sheetfed press (four colors) manufactured by Roland Co., Ltd. so that the ink deposition density of the printing area at the printing speed of 8,000 sheets / hr was 1.80 by using offset ink for each sheet (NEX-M manufactured by Toyo Ink Co., Ltd.) After that, the paper alignment of the printed matter was visually evaluated. If the evaluation is 4 or 3, there is no practical problem.

4: Very good

3: Good

2: slightly behind

1: falling

[Example 1-1]

55 parts by weight (solid content) of heavy calcium carbonate slurry (trade name: CAVITAL 97, particle size of 2 탆 or less: 97%) and a second grade clay (IMERYS, trade name: KCS, 4 parts by weight of a styrene-butadiene copolymer latex as an adhesive, and 6 parts by weight of an oxidized starch (trade name: SK200, manufactured by Nihon Konstch Co., Ltd.) was added in an amount of 6 (solid content) And water was further added to obtain a pigment coating liquid 1 having a solid content concentration of 66% by weight.

A paper having a density of 0.73 g / cm ³ and a basis weight of 98 g / m ² containing 100 wt% of chemical pulp and 13 wt% of light calcium carbonate as a raw material was prepared as a base paper. The pigment coating liquid 1 was coated on both sides of the base paper by a blade coater so that the dry coating amount per side became 15.0 g / m ² , and then dried to obtain a printing paper for printing.

[Example 1-2]

45 parts by weight (solids content) of 55 parts by weight (solids content) of hardened hard calcium carbonate slurry 1 (D50 = 1.02 mu m) and 2 classes of clay (trade name: KCS, D50 = 4.9 mu m) , 4 parts by weight of styrene-butadiene copolymer latex 1 (trade name: PB1537, manufactured by A & L Co., Ltd.) as an adhesive, and 6 parts by weight of oxidized starch (trade name: SK200 manufactured by Nihon Starch Co., Ltd.) were added and water was added thereto to prepare a pigment having a solid concentration of 66% Thereby obtaining a coating solution 1 '.

A coated paper for printing was obtained in the same manner as in Example 1-1 except that the pigment coating liquid 1 'was used instead of the pigment coating liquid 1.

[Comparative Example 1-1]

100 parts by weight (solids content) of a heavy calcium carbonate slurry (trade name: CAVITAL 97, particle size of 2 mu m or less: 97%) as a pigment was used as a pigment, and a styrene / butadiene copolymer latex , 6 parts by weight of oxidized starch (product name: SK200, manufactured by Nihon Astor Co., Ltd.), and water was added to obtain a pigment coating liquid 2 having a solid content concentration of 66% by weight. A coated paper for printing was obtained in the same manner as in Example 1-1 except that the pigment coating liquid 2 was used instead of the pigment coating liquid 1. [

[Comparative Example 1-2]

55 parts by weight (solid content) of heavy calcium carbonate slurry (trade name: CAVITAL 97, particle size of 2 탆 or less: 97%) and a second grade clay (IMERYS, trade name: KCS, 45 parts by weight (solids content) of a styrene-butadiene copolymer latex as a binder and 7 parts by weight of an oxidized starch (trade name: SK200, manufactured by Nihon Konstch Co., Ltd.) And water was further added to obtain a pigment coating liquid 3 having a solid content concentration of 66% by weight. A printing paper for printing was obtained in the same manner as in Example 1-1, except that the pigment coating liquid 3 was used instead of the pigment coating liquid 1.

These results are shown in Table 1.

From Table 1, it is clear that the first printing coated paper of the present invention is a coated paper for mat printing, has excellent quick drying resistance, and has a dynamic friction coefficient higher than the static friction coefficient.

2. Second printing paper

<Evaluation method>

(1) Measurement of pore volume and average pore diameter

The pore volume and average pore diameter of the coated paper were determined by the nitrogen adsorption method. For the measurement, Tristter 3000 manufactured by Shimadzu Corporation was used.

(Preparation of sample)

A paper sample of 40 cm long × 15 cm wide was divided into two layers so as to be uniform in the thickness direction to obtain a laminate including a pigment coating layer and a ground layer. In the case of the double-side coated paper, the number of the laminate is two, and in the case of the single-side coated paper, the laminate is one, and one layer mainly composed of the original layer is obtained. A laminate including a pigment coating layer and a base layer was used as a sample sheet for measurement. In the case of double-sided coated paper, either side was used as a sample sheet for measurement. The basis weight (t) (g / m ² ) of the sample sheet was measured. Four arbitrary points of one sample sheet were selected and cut into a rectangular shape. Then, the measurement sample was placed in the measurement cell so that the absolute dry weight was about 1 to 2 g. The required weight at this time is w (g). Pretreatment was performed overnight in a vacuum state at a treatment temperature of 120 占 폚.

(Measure)

The pore volume and average pore diameter of the measurement sample were measured using the apparatus. Specifically, the pore volume and the average pore diameter of the measurement sample were determined from the desorption isotherm using the BJH method, and the average value of the four samples was obtained. The average value of the pore volume (V ') and the average pore diameter (m' did. The pore volume (V ') was converted into the value per unit coating amount, and the pore volume (V) of the pigment coating layer of the present invention was obtained. The obtained average pore diameter (m ') was taken as the average pore diameter (m) of the pigment coating layer of the present invention. The weight of the pigment coating layer of the sample to be measured is expressed in terms of the weight of the pigment coating layer (g) = the weight of the sample to be measured (w) (g) × the coating amount (c) (g / m ² ) / m ² ). The coating amount (c) (g / m ² ) was determined by a measuring method described later.

The pore volume and average pore diameter of the coated paper were also determined by the mercury penetration method in the same manner as in the nitrogen adsorption method. For the measurement, Auto Pore 9500 manufactured by Shimadzu Corporation was used. The sample was prepared similarly to the nitrogen adsorption method. However, the amount of the sample to be measured was set to about 0.13 g (absolutely weight).

(Coating amount)

The coating amount was measured in accordance with the method described in Japanese Patent No. 5827187. Specifically, the measurement was carried out by the following procedure.

1) The measurement sample (paper) was cut into a size of 5 cm x 5 cm, and the weight (x) after humidity control was measured at a temperature of 23 캜 and a relative humidity of 50%.

2) The sample was placed on a styrene polymer plate so that the pigment coating layer was in contact with the surface of the styrene polymer plate.

3) The styrene polymer was melted and adhered to the pigment coating layer and allowed to cool. The styrene polymer was air-cooled at a temperature of 23 캜 and a relative humidity of 50% for about one day to measure the weight (y).

4) The measurement sample obtained in the whole process was immersed in a copper ethylenediamine solution for about 3 to 4 hours, and then the base layer and the pigment coating layer were delicately peeled off using a brush. This process was repeated until the pulp fibers attached to the pigment coating layer disappeared.

5) The pigment coating layer was washed with water, dried, and the weight (z) was measured after about one day of humidity conditioning at a temperature of 23 캜 and a relative humidity of 50%.

6) The coating amount was calculated by the following formula.

Coating amount (c) (g / m ² ) = (xA) x 400

A = y-z

(2) Blank glossiness

Was measured in the same manner as in Example 1-1.

(3) printing ink repairability

Was measured in the same manner as in Example 1-1.

(4) static friction coefficient and dynamic friction coefficient

Was measured in the same manner as in Example 1-1.

(5) ink drying by sensory evaluation

Was measured in the same manner as in Example 1-1.

(6) Uneven dot

Was measured in the same manner as in Example 1-1.

(7) Printing gloss (gloss difference)

Was measured in the same manner as in Example 1-1.

(Origin)

A paper having a density of 0.73 g / cm ³ and a basis weight of 98 g / m ² containing 100 wt% of chemical pulp and 13 wt% of light calcium carbonate as a raw material was prepared as a base paper.

[Example 2-1]

55 parts by weight (solid content) of a heavy calcium carbonate slurry 1 (trade name: FMT97, manufactured by FAIMATEC, the ratio of particles having a particle diameter of 2 mu m or less by the sedimentation method: 97%, D50 = 0.64 mu m) (Trade name: PB9501, average particle diameter 80 nm, glass transition temperature -20.degree. C.) as an adhesive and 45 parts by weight (solids content) of an acrylic copolymer (trade name: KCS, D50 = 12 parts by weight) and 4 parts by weight of oxidized starch (product name: SK200, trade name, product of Nihon Starch Co., Ltd.), and further water was added to obtain a pigment coating solution 1 having a solid content concentration of 66% by weight.

The pigment coating solution 1 was coated on both sides of the base paper by a blade coater so that the dry coating amount per side was 15.0 g / m ² , and then dried to obtain a printing coated paper.

[Example 2-2]

55 parts by weight (solid content) of a heavy calcium carbonate slurry 1 (trade name: FMT97, manufactured by FAIMATEC, the ratio of particles having a particle diameter of 2 mu m or less by the sedimentation method: 97%, D50 = 0.64 mu m) (Manufactured by A & L, trade name: PB9501, average particle diameter 80 nm, glass transition temperature -20.degree. C.) as an adhesive and 45 parts by weight (solid content) 12 占 폚), and 3 parts by weight of oxidized starch (trade name: SK200, manufactured by Nihon Starch Co., Ltd.), and water was further added thereto to obtain a pigment coating solution 2 having a solid content concentration of 66% by weight.

The coated paper for printing was obtained in the same manner as in Example 2-1 except that the pigment coating liquid 2 was used instead of the pigment coating liquid 1. [

[Example 2-3]

45 parts by weight (solids content) of 55 parts by weight (solids content) of hardened hard calcium carbonate slurry 1 (D50 = 1.02 mu m) and 2 classes of clay (trade name: KCS, D50 = 4.9 mu m) 4 parts by weight of styrene-butadiene copolymer latex 1 (trade name: PB1537, average particle diameter 110 nm, glass transition temperature: 10 占 폚, manufactured by A & L Co.) as an adhesive and 6 parts by weight of oxidized starch (trade name: SK200, Further, water was added to obtain a pigment coating liquid 3 having a solid content concentration of 66% by weight.

A coated paper for printing was obtained in the same manner as in Example 2-1, except that the pigment coating liquid 3 was used instead of the pigment coating liquid 1.

[Comparative Example 2-1]

100 parts by weight (solids content) of heavy calcium carbonate slurry 1 (trade name: FMT97, trade name: FMT97, particle size distribution of particles having a particle diameter of 2 mu m or less: 97%, D50 = 0.64 mu m) 8 parts by weight of styrene-butadiene copolymer latex 2 (trade name: PB9501, trade name: PB9501, average particle diameter 80 nm, glass transition temperature -12 캜) as an adhesive and 6 parts by weight of oxidized starch (product name: SK200, And water was further added to obtain a pigment coating liquid 4 having a solid content concentration of 66% by weight.

A coated paper for printing was obtained in the same manner as in Example 2-1 except that the pigment coating liquid 4 was used instead of the pigment coating liquid 1.

[Comparative Example 2-2]

5 parts by weight (solids content) of 95 parts by weight (solids content) of causticized hard calcium carbonate slurry 1 (D50 = 1.02 μm) and 5 parts by weight of fine particle clay (trade name: Astra Grays, D50 = 0.23 μm) 5.8 parts by weight of styrene / butadiene copolymer latex 1 (trade name: PB1537, average particle size 110 nm, glass transition temperature 10 占 폚) as an adhesive, and 5.3 parts by weight of oxidized starch (trade name: SK200, Water was added to obtain a pigment coating solution 5 having a solid content concentration of 66% by weight.

Subsequently, 20 parts by weight (solid content) of the hardened hard calcium carbonate slurry 1 (D50 = 1.02 mu m) and 80 parts by weight (solid content) of the hardened hard calcium carbonate slurry 2 (D50 = 1.38 mu m) were used as the pigment, , 2.5 parts by weight of styrene / butadiene copolymer latex 1 (trade name: PB1537, average particle diameter 110 nm, glass transition temperature 10 占 폚) and 21 parts by weight of oxidized starch (trade name: SK200, To obtain a pigment coating liquid 6 having a solid content concentration of 66% by weight.

On both sides of the base paper, the pigment coating liquid 6 was coated on both sides with a blade coater so that the dry coating amount per side became 4.5 g / m ² , and then dried to obtain a lower layer coated paper. The pigment coating liquid 5 was coated on both sides of the undercoat so that the dry coating amount per side was 10.5 g / m ² with a blade coater, and then dried to obtain a printing paper for printing.

[Referential Example 2-1]

70 parts by weight of heavy calcium carbonate slurry 1 (trade name: FMT97, D50 = 0.64 占 퐉, trade name: FMT97, D50 = 0.64 占 퐉) as a pigment and 30 parts by weight (solid content) of a primary clay (Premier, 7 parts by weight of styrene-butadiene copolymer latex 2 (trade name: PB9501, trade name: PB9501, average particle diameter 80 nm, glass transition temperature -12 캜) as an adhesive, and oxidized starch (product name: SK200, 3 parts by weight, and water was further added to obtain a pigment coating liquid 7 having a solid content concentration of 66% by weight.

100 parts by weight (solid content) of heavy calcium carbonate slurry 1 (trade name: FMT97, D50 = 0.64 占 퐉, trade name: FMT97, D50 = 0.64 占 퐉) as a pigment was used, and styrene / butadiene copolymer latex 1 (trade name: PB1537, (Trade name: SK200, manufactured by Nihon Starch Co., Ltd.), and further water was added thereto to obtain a pigment coating liquid 8 having a solid content concentration of 66% by weight.

On both sides of the base paper, the pigment coating solution 8 was coated on both sides with a blade coater so that the dry coating amount per side was 8.5 g / m ² , and then dried to obtain a lower layer coated paper. The pigment coating liquid 7 was coated on both sides of the undercoat so that the dry coating amount per side was 20.0 g / m ² with a blade coater, and then dried to obtain a printing paper for printing.

[Referential Example 2-2]

70 parts by weight of a heavy calcium carbonate slurry 2 (trade name: FMT90, a particle diameter of 2 mu m or less in particle diameter: 90%, D50 = 0.94 mu m, manufactured by FUMA TECH CO., LTD.), Styrene-butadiene copolymer latex 2 (trade name: PB9501, average particle diameter 80 nm, glass transition temperature -12 占 폚, manufactured by A & L Co.) was used as an adhesive, and 30 parts by weight (solid content) And 3 parts by weight of oxidized starch (trade name: SK200, manufactured by Nippon Astor Co., Ltd.). Further, water was added to obtain a pigment coating liquid 9 having a solid content concentration of 66% by weight.

A coated paper for printing was obtained in the same manner as in Reference Example 2-1 except that the pigment coating liquid 9 was used instead of the pigment coating liquid 7 as a coating liquid.

[Example 2-4]

70 parts by weight of heavy calcium carbonate slurry 3 (trade name: FMT75, particle diameter of 2 mu m or less in the sedimentation method: 75%, D50 average particle diameter 1.65 mu m) as the pigment, 1 part clay (manufactured by IMERYS Styrene-butadiene copolymer latex 2 (manufactured by A & L, trade name: PB9501, average particle diameter 80 nm, glass transition temperature -12 DEG C, trade name: Premier D50 = 3.22 mu m) ) And 3 parts by weight of oxidized starch (product name: SK200, manufactured by Nihon Astoria Inc.) were further added, and water was added to obtain a pigment coating solution 10 having a solid content concentration of 66% by weight.

A coated paper for printing was obtained in the same manner as in Reference Example 2-1 except that the pigment coating liquid 10 was used instead of the pigment coating liquid 7 as a coating liquid.

[Example 2-5]

55 parts by weight (solids content) of the hardened hard calcium carbonate slurry 1 (D50 = 1.02 탆) and 45 parts by weight (solid content) of the first grade clay (trade name: KCS, D50 = 4.9 탆 by IMERYS CO., LTD. 7.5 parts by weight of styrene-butadiene copolymer latex 1 (trade name: PB1537, trade name: PB1537, average particle size 110 nm, glass transition temperature 10 캜) as an adhesive and 2.7 parts by weight of oxidized starch (trade name: SK200, Water was further added to obtain a pigment coating liquid 11 having a solid content concentration of 66% by weight.

The coated paper for printing was obtained in the same manner as in Example 2-1 except that the pigment coating liquid 11 was used instead of the pigment coating liquid 1. [

[Comparative Example 2-3]

A pigment coating liquid 12 was obtained in the same manner as in Example 2-5, except that fine clay (manufactured by IMERYS, trade name: Astra Grays, D50 = 0.23 μm) was used instead of primary clay. A printing paper for printing was obtained in the same manner as in Example 2-5, except that the pigment coating liquid 12 was used instead of the pigment coating liquid 11.

Table 2 shows the prescriptions and evaluation results of the examples, the comparative examples and the reference examples.

As apparent from Table 2, the larger the pore volume (V) or average pore diameter (m) of the pigment coating layer measured by the nitrogen adsorption method in the printing paper for printing having the base paper and the pigment coating layer thereon, Sincerity also increases. Further, when the coating amount of the pigment coating layer of the coated paper for printing is c, the ink drying property is also increased as V / c or m / c is larger.

Further, the second printing coated paper of the present invention is a coated paper for mat printing which has a large difference between white gloss and printing gloss. In Examples 2-1 to 2-5, the pore volume and average pore diameter , A good ink drying property and a printing ink repairing property can be obtained. In addition, the mat coated papers for Examples 2-1 and 2-3 are provided with a dynamic friction coefficient higher than the static friction coefficient, whereby slippage of the paper is suppressed and the paper alignment is excellent.

On the other hand, in Comparative Examples 2-1 and 2-2, the pore volume and the average pore diameter are low, and the print ink repairability and ink dryness are poor. In addition, as shown in Reference Examples 2-1 and 2-2, when the white paper glossiness is higher than 35%, the pore volume and the average pore diameter can be adjusted within the range of the present invention by decreasing the particle diameter of the coated pigment, It is easy to obtain superior printing ink-repairing property and ink drying property. In the present invention, however, it is excellent in ink repellency and ink drying property as a printing paper for mat printing in which gloss is suppressed.

3. Evaluation of ink fastness

[Comparison of nitrogen adsorption method and mercury intrusion method]

The ink fast drying properties of the coated paper for printing obtained in Reference Examples 2-1, 2-2 and 2-4 were quantitatively evaluated by the following methods.

&Lt; Quantitative evaluation of ink fast drying property &

0.8 cc of a standard tac ink for flat plate was developed on a rubber roll using an RI printing tester (manufactured by Ishikawajima Industrial Machinery Co., Ltd., type RI-3), and three times so that the ink amount became uniform at a printing speed of 130 rpm Overlapped and printed on the printing paper. The ink printed on the coated paper was transferred to paper every 2 minutes from 2 minutes to 20 minutes after printing, and the Y value (brightness) of the ink transferred to the paper was measured with a portable spectrophotometer (X-Rite 520, . The Y value represents the degree of ink transferred to the paper without drying. The standard of ink quick dry property was set to Y = 80, and the time for achieving this was defined as a quantitative index of dryness.

The results are shown in Table 3, Figs. 1 and 2. As the pore volume and the average pore diameter measured by the nitrogen adsorption method become larger, the quick drying property of the ink is improved. This tendency follows the relationship of the above-described expression (3). On the other hand, this correlation was not found in the mercury porosimetry method. From the above, it is clear that by using the nitrogen adsorption method, it is possible to more accurately measure the quick drying property of the ink.

Claims (21)

The white paper gloss according to JIS-P8142 is less than 30%, and
A coated article having a dynamic coefficient of friction greater than a static coefficient of friction in static and dynamic coefficients of friction measured in accordance with ISO 15359. The method according to claim 1,
A pigment, and a pigment coating layer comprising a pigment and an adhesive provided thereon,
Wherein the pigment comprises kaolin or clay,
Wherein the adhesive comprises 20 to 50% by weight of latex in the total adhesive. 3. The method according to claim 1 or 2,
Coated paper as a printing paper. The method of claim 3,
JAPAN TAPPI Paper Pulp Test Method No. 46, wherein the print ink has a water-repellency of 20 to 35. And a step of coating a pigment coating liquid containing a pigment and an adhesive on the base paper,
Wherein the pigment comprises kaolin or clay,
The method for producing a coated paper according to any one of claims 1 to 4, wherein the adhesive comprises 20 to 50% by weight of latex in the total adhesive. (V) of not less than 0.04 cm &lt; ³ &gt; / g as measured by a nitrogen adsorption method of the pigment coating layer, and a pigment coating layer provided thereon. The method according to claim 6,
Wherein the pigment coating layer has an average pore diameter (m) of 30 nm or more as measured by a nitrogen adsorption method. 8. The method according to claim 6 or 7,
Wherein the pore volume (V) is 0.09 cm &lt; ³ &gt; / g or less. 9. The method according to any one of claims 6 to 8,
Wherein the average pore diameter (m) is 60 nm or less. 10. The method according to any one of claims 6 to 9,
Wherein the outermost layer of the coated substrate is a pigment coating layer and the dynamic friction coefficient and the dynamic friction coefficient of the outermost pigment coating layer side measured according to ISO 15359 are larger than the static friction coefficient. 11. The method of claim 10,
Wherein the outermost pigment coating layer comprises 25 to 75% by weight of calcium carbonate in the whole pigment. 12. The method of claim 11,
Wherein the calcium carbonate is heavy calcium carbonate. 12. The method of claim 11,
Wherein said calcium carbonate is hard calcium carbonate. 14. The method according to any one of claims 10 to 13,
Wherein said outermost pigment coating layer comprises 20 to 50% by weight of kaolin or clay in the total pigment. 15. The method according to any one of claims 10 to 14,
Wherein the outermost pigment coating layer comprises an adhesive and comprises 20 to 80% by weight of latex in the adhesive. 16. The method according to any one of claims 6 to 15,
A pore volume (V) of the pigment coating layer (cm ³ / g) × a coated amount of ^{(c) (g / m 2} ) the total pore volume is defined as a (cm ³ / m ²⁾ is, 0.55 ~ 4.50cm ³ / m ^Two- person pottery equipment. 17. The method according to any one of claims 6 to 16,
A coating material having a glossiness of less than 35% by JIS-P8142. 18. The method according to any one of claims 6 to 17,
JAPAN TAPPI Paper Pulp Test Method No. 46, which is a printing-use coating material having a printability of 20 to 35. The coated substrate according to any one of claims 6 to 18, which is a coated paper. A step of measuring a pore volume (V) or an average pore diameter (m) of the pigment coating layer in a coated substrate having a sheet-like substrate and a pigment coating layer provided thereon by a nitrogen adsorption method, and
And the ink drying property is also increased as V or m is increased. 21. The method of claim 20,
Further comprising a step of measuring a coating amount (c) of the pigment coating layer,
And evaluating ink dryness based on the relationship that the larger the V / c or m / c is, the higher the ink drying property is.

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