JP2001081694A - Pigment coated paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of making a white paper part dirty by the transfer of a printed ink by bringing the white paper part into contact with a printed part in a pigment coated paper during printing or in a step or the like for bookbinding after the printing. SOLUTION: This pigment coated paper hardly causing transfer of an ink is obtained by coating a coating composition consisting essentially of a pigment and an adhesive on a base paper, and drying the resultant paper. The coating composition comprises (A) >=65 pts.wt. ground and/or precipitated calcium carbonate having >=3 μm average particle diameter, (B) 5-30 pts.wt. adhesive component, and (C) 0.2-3 pts.wt. metal salt of a fatty acid, having 6-30 μm average particle diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pigment coated paper. More specifically, the present invention relates to a pigment-coated paper having a small problem that ink in a printed portion transfers to a blank portion during printing or bookbinding, and stains the blank portion.

[0002]

2. Description of the Related Art Conventionally, there is an increasing demand for pigment-coated paper in which a coating composition containing a pigment and an adhesive as a main component is coated on base paper for the purpose of improving printability. Among them, matte coated paper, so-called matte coated paper such as dull coated paper is widely used for high-grade art printing, catalogs, brochures, calendars and commercial publishing papers, and usually uses heavy or light calcium carbonate. By blending in a large amount, the gloss of white paper is reduced, the whiteness is improved, and the ink acceptability is improved. However, these pigment coated papers
There is a problem that the printed ink is transferred and the white paper portion is stained by contact between the printed portion and the blank paper portion during printing or in a bookbinding process after printing (hereinafter referred to as rubbing stain). In particular, the problem of the rubbing stain was large in the matte coated paper described above.

As a method for solving the present invention, a method of incorporating 20 to 80% by weight of a delaminated clay having an average particle diameter of 0.4 to 1.0 μm with respect to all the pigment components (Japanese Patent Laid-Open No. 5-5297) Gazette), the average particle size is 0.5 to
A method in which a base paper is coated with a coating composition containing 50 to 80% by weight of 1.5 μm calcium carbonate and 20 to 50% by weight of kaolin, and further subjected to a high-temperature soft calendering treatment at 100 ° C. or higher (Japanese Patent Laid-Open No. Hei 5 (1994)). JP-A-117995), an undercoating coating liquid containing 20 parts by weight or more of calcium carbonate having an average particle diameter of 3 μm or less based on 100 parts by weight of the pigment, and further, 60 parts by weight of clay with respect to 100 parts by weight of the pigment Of a topcoat coating solution containing at least 3 parts by weight
JP-A-214699), a fatty acid salt emulsion as an ink transfer inhibitor was added in an amount of 1.2 to 100 parts by weight of a pigment.
There is known a method of coating a coating composition containing 2.0 parts by weight (JP-A-6-158594).

[0004]

However, the methods described in JP-A-5-5297, JP-A-5-117959 and JP-A-5-214699 are insufficient in the effect of preventing rubbing and dirt. When the laminating clay or kaolin is added in a high proportion, adverse effects such as a decrease in whiteness and ink acceptability also occur. Also, JP-A-6
JP-A-158594 discloses an example in which the average particle diameter is 5 μm.
The use of the following fatty acid salt emulsions is disclosed, but the use of these emulsions was insufficient in the effect of preventing rubbing. As described above, the effect of preventing rubbing with the conventional method is insufficient, and there has been a demand for the development of a pigment-coated paper having a better effect of preventing rubbing.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve such problems, and as a result, have completed the present invention. That is, the present invention provides a pigment-coated paper obtained by coating a coating composition containing a pigment and an adhesive as main components on a base paper, and drying the pigment-coated paper with respect to 100 parts by weight of all pigments in the coating composition. (A) heavy particles having an average particle diameter of 3 μm or less and / or
Alternatively, 65% by weight or more of light calcium carbonate, 5 to 30 parts by weight of an adhesive component (B), and (C) an average particle size of 6 to 3
Pigment-coated paper containing 0.2 to 3 parts by weight of a 0 μm fatty acid metal salt.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The fatty acid metal salt which can be used in the pigment coated paper of the present invention is an alkali metal of a fatty acid (sodium,
Substantially water-insoluble metal salts of fatty acids excluding salts such as potassium and ammonium). Dispersions of fatty acid alkali metal salts, ammonium salts, etc., become completely aqueous in the low concentration region when added to the paper coating solution,
Phenomena such as an increase in viscosity and an increase in foaming of the paper coating liquid occur, which is not preferable.

[0007] The fatty acid metal salt of the present invention is preferably a compound having 8 carbon atoms.
The above saturated or unsaturated fatty acids (caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachiic acid, saturated fatty acids such as behenic acid, octenoic acid, tetradecenoic acid, hexadecenoic acid, oleic acid,
Linoleic acid, unsaturated fatty acids such as linolenic acid), oxy fatty acids (fatty acids having a hydroxyl group such as 12-hydroxystearic acid and ricinoleic acid), or a mixture of two or more thereof, with magnesium, calcium, strontium,
Examples include salts with barium, zinc, cadmium, aluminum and the like, or mixtures of these metals. Among these, preferred are magnesium, calcium, zinc, barium salts of saturated fatty acids having 12 to 20 carbon atoms, unsaturated fatty acids or oxy fatty acids or a mixture of these salts, and more preferably palmitic acid, stearic acid. , Oleic acid, linoleic acid, magnesium, calcium, zinc salts or mixtures of these salts.

The average particle size (50% volume average particle size by a laser diffraction type particle size distribution analyzer) of the fatty acid metal salt is
It is usually 6 to 30 μm, preferably 6 to 25 μm, more preferably 10 to 20 μm. The fatty acid metal salt dispersion used as a lubricant for coated paper has an average particle diameter of 6 μm or less.
If it is larger than 0 μm, problems such as the glossiness of white paper on the surface of the coated paper, a decrease in smoothness, and the occurrence of streaks will occur. In addition, the shape of the fatty acid metal salt is preferably more spherical, plate-like,
A needle-like material does not provide a sufficient effect of preventing rubbing.

[0009] The fatty acid metal salt dispersion of the present invention is obtained by a melting method,
Fatty acid metal salts obtained by semi-solid method, wet direct method, solid phase method, solvent method, metathesis method, etc., are ground beforehand and dispersed in water in the presence of a dispersing agent, or water, fatty acid metal salt, emulsifying dispersant In a reaction vessel, heated above the melting point, emulsified and dispersed by stirring, and then cooled. The emulsifying dispersant used for emulsifying and dispersing the aqueous dispersion is not particularly limited as long as it can disperse and emulsify the fatty acid metal salt in water. Non-ionic surfactants, anionic surfactants, amphoteric surfactants Alternatively, a water-soluble polymer can be used. The use ratio of the emulsifying dispersant is, based on 100 parts by weight of the fatty acid metal salt, a nonionic surfactant, an anionic surfactant, an amphoteric surfactant,
Alternatively, at least one emulsifying dispersant selected from water-soluble polymers is contained in an amount of 0.3 to 50 parts by weight, preferably 0.5 to 50 parts by weight.
It is 20 parts by weight, more preferably 0.5 to 10 parts by weight. If the amount of the emulsifying dispersant is less than 0.3 parts by weight, a stable aqueous dispersion cannot be obtained. If the amount exceeds 50 parts by weight, the coated paper properties such as water resistance, printability, (ink acceptability, pick strength, etc.) will be poor. descend.

Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether (polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, etc.), polyoxyethylene alkyl ether, (polyoxyethylene stearyl ether,
Polyoxyethylene secondary tridecyl ether, etc.), fatty acid polyethylene glycol esters (polyethylene glycol laurate, polyethylene glycol oleate, etc.), fatty acid alkanolamides (lauric acid diethanolamide, stearic acid monoethanolamide, etc.), fatty acid sorbitan Esters (such as sorbitan oleate and sorbitan polyoxyethylene laurate).

Examples of the anionic surfactant include sulfonates (dodecylbenzene sulfonate, dioctyl sulfosuccinate, alpha olefin sulfonate, secondary alkane sulfonate, polystyrene sulfonate, formalin naphthalene sulfonate). Condensates, etc.), sulfates (lauryl alcohol sulfate, polyoxyethylene lauryl ether sulfate, polyoxyethylene nonyl phenyl ether sulfate, etc.), phosphates (polyoxyethylene nonyl phenyl ether phosphate) Salts) and fatty acid ester salts (stearate, oleate, etc.). Examples of the type of the salt include alkali metal salts such as lithium, sodium and potassium, alkaline earth metal salts such as calcium and magnesium, amine salts such as monoethanolamine and alkylamine, and ammonium salts.

Examples of the amphoteric surfactant include amino acid type (such as sodium laurylaminopropionate) and betaine type (such as stearyl dimethyl betaine and lauryl dihydroxyethyl betaine).

Examples of the water-soluble polymer include starch, gum arabic, gum tragacanth, dextran, xanthan gum, and pullulan as natural polymers, and synthetic polymers such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyethylene glycol, and polypropylene glycol. And polyvinyl ether.

As the stirring mixer, a propeller type stirring machine,
Dissolvers, homomixers, ball mills, sand mills, ultrasonic dispersers, kneaders, line mixers and the like can be used.

Examples of the disperser include a propeller type stirrer, a piston type high-pressure emulsifier, a homomixer, an ultrasonic emulsifier / disperser, a pressurized nozzle type emulsifier, a high-speed rotating high-shear type stirrer / disperser, a colloid mill, glass beads, Media type dispersing machine that pulverizes and disperses using various media such as steel balls,
For example, a sand grinder, an agitator mill, a ball mill, an attritor, and the like can be used, and two or more of these facilities can be used in combination.

In the present invention, the amount of the fatty acid metal salt added is
Usually 0.2 to 3 parts by weight, preferably 0.3 to 2 parts by weight, more preferably 0.5 to 2 parts by weight based on 100 parts by weight of the total pigment.
Parts by weight. If the amount is less than 0.2 part by weight, the effect of preventing rubbing is not sufficient, and it is not necessary to add more than 3 parts by weight. Also, an excessive amount may adversely affect the smoothness of the coated paper and the ink adhesion.

The dispersion of the fatty acid metal salt obtained in the present invention contains or mixes an antioxidant, an ultraviolet absorber, a waterproofing agent, an antiseptic / antifungal agent, a bactericide, an antifoaming agent, a fragrance, a dye or a pigment. You may let it.

The pigment-coated paper of the present invention contains, as a pigment component,
It is necessary to blend 65 parts by weight or more of heavy and / or light calcium carbonate having an average particle diameter of 3 μm or less with respect to 100 parts by weight of all pigments. If the average particle size exceeds 3 μm, the smoothness and ink adhesion of the coated paper will decrease, and if the amount is less than 65 parts by weight, whiteness and ink receptivity will decrease, and glossiness of the white paper will easily increase. It is highly likely that the texture of the eraser coated paper will be impaired. Other pigment components include kaolin clay, delaminated clay, titanium oxide,
One or more ordinary pigments for coated paper, such as satin white, aluminum hydroxide, talc, silica, calcium sulfate, and plastic pigment, are appropriately selected and used.

As the adhesive component of the present invention, styrene
Butadiene, styrene / acrylic, vinyl acetate, acrylic, ethylene / vinyl acetate, methyl methacrylate / butadiene copolymer latex or oxidized starch, phosphated starch, hydroxyethylated starch, polyvinyl alcohol, casein Such general adhesives for pigment-coated papers may be used alone or in combination.
These adhesives are usually used in an amount of 5 to 100 parts by weight of the pigment.
It is used in an amount of 30 parts by weight, preferably about 6 to 25 parts by weight. If the amount is less than 5 parts by weight, the coating layer strength is not sufficient, and if the amount exceeds 30 parts by weight, ink receptivity,
It is conceivable that printability such as inking property may be reduced. In addition, the pigment-coated paper of the present invention may contain various auxiliaries, such as a dispersant, a water-proofing agent, a water-retaining agent, a fluidity improver, an antifoaming agent, a colorant, and a preservative, which are blended in a general coating composition. Can be used as needed.

The solid content concentration of the coating composition of the present invention varies depending on the coating apparatus and the desired coating amount.
７０70% by weight, preferably 40-65% by weight. The coating composition adjusted in this manner is used for coating equipment such as a blade coater, an air knife coater, a roll coater, a curtain coater, a bar coater, a gravure coater, and a size press coater which are used in the usual pigment coated paper production. A single layer or two or more layers are coated on one or both sides of the base paper by an on-machine or off-machine coater provided. As the base paper, base paper or synthetic paper mainly composed of pulp fibers having a basis weight of 40 to 300 g / m ² and used in the production of general pigment coated paper can be used. The coating amount of the coating composition is usually 5 to 40 g / m in dry weight per side.
² , 10 to 25 g / m ^{2 in} terms of blank paper quality and printability
It is preferred to be coated within the range. Further, for the pigment-coated paper of the present invention, a surface treatment device such as a super calender, a mat calender, a soft nip calender, and a machine calender may be used for adjusting glossiness of white paper and improving printability. The glossiness of the white paper of the pigment coated paper of the present invention is not particularly limited. However, since the effect of preventing rubbing stain on the matte coated paper is higher than that of the high gloss paper, JIS. P
It is suitable to target a range in which the glossiness of 75-degree blank paper according to the 8142 method is about 10 to 50%. Further, as the glossiness of the white paper decreases, the problem of rubbing stains increases. Therefore, the glossiness of the white paper is preferably from 10 to 45%, particularly preferably from 15 to 45%.

[0021]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited to these examples. In addition, evaluation of the white paper gloss, surface smoothness, rubbing stain prevention effect of the pigment coated paper obtained in Examples and Comparative Examples, and the method of measuring the particle size of the pigment and fatty acid metal salt used in Examples and Comparative Examples are as follows. Shown in Blank gloss: JIS. Using a gloss meter manufactured by Nippon Denshoku Co., Ltd., the gloss at 75 degrees was measured according to the method of P8142, and the gloss of the white paper was compared. The higher the number, the higher the glossiness of the blank paper. Surface smoothness: The smoothness was measured using an Oken type smoothness meter. The higher the number, the higher the smoothness. Rub stain prevention effect: Using a RI-1 type printing tester on the surface of the pigment coated paper obtained in Examples and Comparative Examples, Dainippon Ink Offset Printing Ink (Graph-G Black) 0.5
Printing was performed using the cc and left overnight. Using a friction coefficient measuring device manufactured by Tester Sangyo Co., Ltd., the printed test paper and white paper were brought into contact with each other to apply a load of 1,000 g and a speed of 200 mm /
Rubbing was performed five times per minute, and the density of the ink transferred from the printed paper to the white paper was visually judged to evaluate the effect of preventing rubbing stains. ◎ Substantially no transfer of ink ○ Substantially transfer of ink △ High transfer of ink × Extremely high transfer of ink Particle size measurement: Laser light diffraction / scattering method particle size distribution analyzer (MICROTRACHRA, Leeds & North)
(manufactured by Hrup Co.) under the following conditions. As the particle diameter, the particle diameter when the volume percentage became 50% was used as the average particle diameter. Sample solid concentration: 2.5% Flow rate: 40 ml / sec Measurement time: 30 sec Measurement frequency: 2 times

Examples 1 to 15 and Comparative Examples 1 to 9 Heavy calcium carbonate having an average particle diameter of 1.2 μm (manufactured by Sankyo)
Powder, escalon # 2000) 70 parts by weight, kaolin (d
30 parts by weight of a dispersant (Sungel Hard, UW-90)
Nopco, SN-Dispersant 5040) 0.2 weight
And dispersed in water using a styrene-butadiene latet.
12 parts by weight of kusu (Japanese synthetic rubber, JSR0696), acid
Starch (Japan Food Processing, MS-3600) 3 parts by weight
Further, fatty acid metal salts A to G shown in Table 1 (Examples 1 to 5)
15) Add H to O (Comparative Examples 1 to 8) and add solid concentration 6
4% of the coating composition was obtained. This coating composition is weighed 64 g.
/ M ² 15g / m coating amount on high quality paper base paper² Will be
Apply using a blade coater, dry and apply pigment
I got the paper. For comparison, a coated set that does not contain fatty acid metal salts
A pigment-coated paper was prepared by applying the composition in the same manner and drying (compared to
Comparative Example 9).

Comparative Example 10 A coating composition containing no fatty acid metal salt was prepared in the same manner as in Comparative Example 9 except that 30 parts by weight of heavy calcium carbonate and 70 parts by weight of kaolin were used. Examples 1 to 1
Table 5 shows the evaluation results of rubbing stains on the pigment coated papers obtained in Comparative Examples 1 to 10.

Examples 16 to 30, Comparative Examples 11 to 19 45 parts by weight of heavy calcium carbonate having an average particle diameter of 1.2 μm (Sankyo Milling, Escalon # 2000), light calcium carbonate having an average particle diameter of 0.8 μm (Okutama Kogyo Co., Ltd.) , Tamapearl TP-222H) 45 parts by weight, kaolin (UW-9)
0) 10 parts by weight were dispersed in water using 0.2 parts by weight of a dispersant (San Nopco, SN-Dispersant 5040), and styrene-butadiene latex (Nippon Synthetic Rubber,
JSR0696) 12 parts by weight and oxidized starch (Japan Food Processing Co., Ltd., MS-3600) 3 parts by weight, and further, fatty acid metal salts A to G shown in Table 1 (Examples 16 to 30), H to O
(Comparative Examples 11 to 18) were added to obtain a coating composition having a solid content of 64%. The coated composition coated with a blade coater so coated amount woodfree paper sheet having a basis weight of 64 g / m ² is 15 g / m ^2, and dried to obtain a pigment coated paper. For comparison, a coating composition containing no fatty acid metal salt was similarly coated and dried to prepare a pigment-coated paper (Comparative Example 1).
9). Further, the pigment coated papers obtained in Examples 16 to 30 and Comparative Examples 11 to 19 were subjected to a temperature of 30 ° C. and a nip pressure of 50 kg / c.
Supercalendering was performed under the conditions of m, and the results of evaluation of rubbing stains on the obtained pigment-coated paper are shown in Table 3.

Examples 31 to 45, Comparative Examples 20 to 29 70 parts by weight of light calcium carbonate (Okutama Kogyo, Tamapearl TP-222H) having an average particle diameter of 0.8 μm, and 30 parts by weight of kaolin (UW-90) were used as a dispersant ( San Nopco, SN
Dispersant 5040) was dispersed in water using 0.2 parts by weight, and 25 parts by weight of styrene-butadiene latex (Nippon Synthetic Rubber, JSR0696) and 2 parts by weight of oxidized starch (Japan Food Processing, MS-3600) were added. Table 1
Fatty acid metal salts A to G (Examples 31 to 45), H
To O (Comparative Examples 20 to 27) were added to obtain a coating composition having a solid content of 64%. This coating composition was treated with a basis weight of 64 g / m ^2.
Was coated with a blade coater so that the coating amount was 15 g / m ² , and dried to obtain a pigment coated paper. For comparison, a coating composition containing no fatty acid metal salt was similarly coated and dried to prepare a pigment-coated paper (Comparative Example 2).
8).

Comparative Example 29 A coating composition containing no fatty acid metal salt was prepared in the same manner as in Comparative Example 28 except that 30 parts by weight of light calcium carbonate and 70 parts by weight of kaolin were used. Example 3
Table 4 shows the evaluation results of rubbing stains of the pigment coated paper obtained in Examples 1 to 45 and Comparative Examples 20 to 29.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

[0030]

[Table 4]

[0031]

As is clear from Tables 2, 3 and 4,
The pigment coated paper of the present invention has a high effect of preventing the problem that the printed ink is transferred and the white paper portion is stained by the contact between the printed portion and the white paper portion, and is extremely useful in practice.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4L055 AG11 AG12 AG27 AG34 AG48 AG62 AG76 AG89 AG97 AH02 AH37 AJ04 EA16 EA30 EA32 FA30 GA19

Claims (2)

[Claims] 1. A pigment-coated paper obtained by coating a base paper with a coating composition containing a pigment and an adhesive as a main component, and drying the coating composition, based on 100 parts by weight of all pigments in the coating composition. (A) 65 and more parts by weight of heavy and / or light calcium carbonate having an average particle diameter of 3 μm or less, (B) 5 to 30 parts by weight of an adhesive component, and (C) fatty acid metal having an average particle diameter of 6 to 30 μm. Pigment-coated paper containing 0.2 to 3 parts by weight of a salt. 2. The pigment coating according to claim 1, wherein the fatty acid metal salt is a salt of a saturated or unsaturated fatty acid having 12 to 22 carbon atoms or a mixture thereof and magnesium, calcium, zinc, barium or a mixture thereof. paper.