KR20160135832A - Paper filled with rosette-type precipitated calcium carbonate - Google Patents

Abstract

A problem to be solved by the present invention is to provide a paper in which a papermaking chemical is effective even when a lot of internal transfer materials are blended, and a decrease in strength is suppressed. According to the present invention, there is provided a paper in which rosetta-type hard calcium carbonate coagulated with primary particles is internally packed, the rosetta type hard calcium carbonate has a BET specific surface area of 1.0 to 8.0 m2 / g, an average particle diameter (D50) Is 3.0 to 15.0 mu m.

Description

{PAPER FILLED WITH ROSETTE-TYPE PRECIPITATED CALCIUM CARBONATE}

The present invention relates to a paper in which rosetta type hard calcium carbonate is internally packed.

In general, paper is internally filled with cellulose-based fiber material as an inorganic material, and the transfer material is added to improve optical properties, mainly whiteness and opacity, which tend to become insufficient with cellulose-based fiber material alone. Recently, in order to improve the environmental consciousness and reduce the production cost, measures have been taken to reduce the amount of the cellulose fiber material made of wood as a raw material, and instead to increase the charge rate in the paper. However, when the electric charge is increased, the optical properties are improved while the tensile strength, the tear strength, and the stiff heat size are lowered. In general, chemicals such as a paper strength enhancer and an internal sizing agent are added in order to compensate for degraded strength characteristics and size, but the use of a large amount not only increases the load on the production cost, There is also a problem of contamination in the system.

On the other hand, in recent years, paper making has progressed to paper making, and light calcium carbonate is most widely used as a current charge. The reason for this is that whiteness is higher than that of talc and clay, and the particle shape, particle size, and aggregation state can be adjusted depending on the synthesis method, and physical properties imparted to the paper can be easily controlled. For this reason, much research has been conducted up to now, including the particle shape and the particle diameter of hard calcium carbonate for electric discharge.

For example, Patent Document 1 discloses that primary particles having an average particle size of 4.0 to 15.0 mu m and a BET specific surface area of 5.0 to 10 m < 2 > / g and having a needle-like and columnar shape and / It has been proposed to use calcium.

Patent Document 2 discloses that hard calcium carbonate having a secondary particle size of 1 to 10 탆 in which primary particles of spindle-shaped calcium carbonate are floc agglomerated and has a BET specific surface area of 8 to 20 m 2 / g, Lt; RTI ID = 0.0 > g / cm3 < / RTI > and 3.5 cm < 3 > / g.

Further, in Patent Document 3, it has been proposed to reduce the drying load at the time of paper manufacture by using talc in combination with rosetta-type calcium carbonate aggregated in the form of chestnut with the primary particles of spindle-shaped calcium carbonate.

Japanese Unexamined Patent Application Publication No. 2013-60692 Japanese Patent No. 4571583 Japanese Unexamined Patent Application Publication No. 2012-172287

When needle-like or pillar-shaped calcium carbonate as described in Patent Document 1 exists as primary particles, it is easy to orient in the surface of the coating layer and in the coating layer from the characteristics of the shape, and the MD (paper grain flow direction) There is a drawback that the difference in strength in the direction of the paper width (paper width direction) tends to increase. In addition, when the aggregate of needle-like and columnar primary particles described in Patent Document 1 is entrapped in paper, the needle-like shape of the primary particles of the hard calcium carbonate and the tip of the columnar shape are very thin, Therefore, there is a drawback that the formation of fiber-to-fiber bond is inhibited and the interlaminar strength is weakened.

Further, the hard calcium carbonate of Patent Document 2 has a problem that primary particles are spindle-shaped, secondary particles are formed by floc agglomeration, and BET specific surface area is high. The use of a high-specific-surface-area charge increases the amount of paper-making chemicals adsorbed on the surface of the charge, so it is necessary to add a large amount of chemicals in comparison with the case of using a charge- .

Patent Document 3 discloses that when the rosette type hard calcium carbonate and talc are used in combination, the drying load becomes small. However, no study has been made on the relationship between the shape of the rosette type hard calcium carbonate and the strength of the paper.

In view of the above circumstances, a problem to be solved by the present invention is to provide a paper in which the effect of the papermaking agent is improved even when a lot of internal transfer materials are blended, and the decrease in strength is suppressed.

As a result of intensive studies, the present inventors have found that the above problems can be solved by using hard calcium carbonate having a specific particle shape.

Although not limited thereto, the present invention includes inventions of the following aspects.

(1) A paper filled internally with rosetta type hard calcium carbonate aggregated in the form of radially primary particles, wherein the rosetta type hard calcium carbonate has a BET specific surface area of 1.0 to 8.0 m 2 / g and an average particle diameter (D50) of 3.0 to 15.0 Mu m.

(2) The paper according to (1), wherein the Rosetta type hard calcium carbonate has a BET specific surface area of not less than 3.0 m 2 / g.

(3) The paper according to (1) or (2), wherein the average particle size (D50) of the rosetta type hard calcium carbonate is 3.5 占 퐉 or more.

(4) A paper as described in any one of (1) to (3), wherein the ash content in the paper is 10% by weight or more.

(5) The paper according to any one of (1) to (4), wherein at least 10% by weight of the entrails are rosetta type hard calcium carbonate.

(6) The paper described in any one of (1) to (5), which is not known without having a pigment coating layer.

According to the present invention, by using rosetta type hard calcium carbonate having a specific BET specific surface area and an average particle size as a transfer material, it is possible to obtain a paper having strength and size property such as tensile strength, Can be obtained.

Fig. 1 is an electron micrograph showing a rosetta type hard calcium carbonate dispersed in a liquid (micron in the figure means mu m).

The present invention relates to a paper in which a rosette type hard calcium carbonate is filled as a charge.

Rosetta type hard calcium carbonate

The hard calcium carbonate is generally produced by a liquid-gas method (carbonic acid method) in which carbonic acid gas is blown into a slaked lime slurry and a liquid-liquid method (solubilization method) in which sodium carbonate or the like is used In the present invention, light calcium carbonate obtained by any process can also be used. In general, hard calcium carbonate has a crystal system such as a calcite type or an argonite type and has various shapes such as a columnar shape, a needle shape, a spiral shape, and a cubic shape.

In the present invention, a rosette type hard calcium carbonate having a specific average particle diameter and BET specific surface area is used. The inventors of the present invention have found that, when rosette hard calcium carbonate aggregated in the form of radial primary particles is used as an internal transfer material, a paper excellent in strength characteristics such as tensile strength and tear strength is obtained. The hard calcium carbonate having a shape other than the rosuter type does not become a paper excellent in strength characteristics such as tensile strength and tear strength as compared with the present invention, even if the average particle diameter and BET specific surface area are in the range of the present invention.

The reason why an excellent effect is obtained in the present invention is not clear, but the hard calcium carbonate of the present invention is characterized in that the average particle size is relatively large and the BET specific surface area is relatively small. Generally, when hard calcium carbonate having the same particle shape and average particle size is compared, the smaller the BET specific surface area, the larger the primary particles. In the present invention, it is considered that these large primary particles aggregate in a rosetta form, and secondary particles having a large average particle size are influential. In addition, the hard calcium carbonate of the present invention is difficult to abrade the wire of the paper machine although it is a comparatively large particle. From this point of view, it is considered that the shape of the rosetta type contributes.

The rosette type hard calcium carbonate used in the present invention is one in which primary particles of calcite-based calcium carbonate or aragonite-based calcium carbonate coagulate radially to form secondary particles, and compared with calcium carbonate of other types High specific surface area and absorptivity. Here, in the radial shape, for example, the longitudinal direction of each primary particle is radially extended from the vicinity of the center of the secondary particle. In addition, the width (diameter) of the base portion of each primary particle is slightly larger and thinner toward the tip end. The shape of the primary particles is preferably a spindle shape, but may be a needle shape or a columnar shape.

In general, hard calcium carbonate is advantageous in terms of production cost and operability, and also excellent in that paper having a low opacity at a low addition amount is obtained. In addition, since the rosetta type hard calcium carbonate of the present invention is highly blended with the base paper due to its special shape, the opacity of the base is greatly improved, effectively preventing leakage.

1 is an electron micrograph showing an example of rosetta type hard calcium carbonate dispersed in a liquid. The rosette type hard calcium carbonate has a feature that strong bonding of the particles is strong and secondary particles are hard to be separated from each other as compared with a form in which primary particles are irregularly aggregated such as floc agglomeration. Therefore, the particle shape can be easily maintained even when the paper is filled in, and the characteristics of the paper can be effectively improved.

The rosette type hard calcium carbonate of the present invention needs to have an average particle size (D50) measured by laser diffraction method of not less than 3.0 mu m and not more than 15.0 mu m. When the D50 exceeds 15.0 占 퐉, the yield of the electric charge is improved, but the electric charge in the paper is localized, so that the tensile strength and the tear strength are lowered. If the D50 is less than 3.0 mu m, the distribution of the charge in the paper becomes uniform, but on the other hand, the charge yield is deteriorated, and therefore it is necessary to apply the chemicals such as the yield improving agent, and the load on the production cost is increased. Further, since the amount of ash and chemicals in white water increases, there arises a problem of contamination in the system such as scale deposition. Therefore, in order to obtain a paper having a high yield as a charge and having excellent strength characteristics and dimensional stability of paper, D50 is preferably 3.5 mu m or more, more preferably 4.0 mu m or more, and further preferably 4.5 mu m or more. The upper limit of D50 is preferably 10.0 占 퐉 or less, and more preferably 8.0 占 퐉 or less.

Further, the rosetta type hard calcium carbonate of the present invention is preferable because the particle size (d50) of 50 volume% of the particle size distribution curve measured by the X-ray transmission method is 2.0 to 5.0 m, , And particularly preferably 2.2 to 3.4 mu m.

The BET specific surface area of the rosette type hard calcium carbonate of the present invention should be 1.0 or more and 8.0 m2 / g or less. If it is less than 1.0 m < 2 > / g, the ink and water absorbability at the time of printing is deteriorated, and the drying property is lowered. In addition, when the BET specific surface area is too small, scattering of light is small, leading to a decrease in opacity. On the other hand, when the BET specific surface area exceeds 8.0 m 2 / g, the water absorbability of the ink and water is good, but the water absorbency of the paper making agent is also improved, and the effect of the additive such as yield agent, The BET specific surface area is preferably 3.0 m 2 / g or more, more preferably 4.0 m 2 / g or more, and still more preferably 5.0 m 2 / g or more in order to obtain good ink and water absorbability and to obtain a high drug addition effect. It is preferably not more than 7.5 m 2 / g, more preferably not more than 7.0 m 2 / g, even more preferably not more than 6.5 m 2 / g. In any embodiment, the BET specific surface area is preferably 4.5 m 2 / g to 8.0 m 2 / g, more preferably 6.0 m 2 / g to 8.0 m 2 / g.

The present invention is not particularly limited to the production method of the light calcium carbonate, but it is preferable that the step (A) and the step (A) of obtaining the slaked lime by adding the digestion water in the molar ratio to the quicklime of 2.5 or less by the " liquid- A step (B) of obtaining a slaked slurry by mixing the slaked lime and water, and a step (C) of carbonating the slaked slurry by blowing a carbon dioxide-containing gas into the slaked slurry by appropriately adjusting the temperature and stirring conditions If it is calcium carbonate, the desired particle shape, particle diameter, and BET specific surface area are easily obtained and the most preferable.

Rosette type hard calcium carbonate-impregnated paper

The paper of the present invention in which rosetta type hard calcium carbonate is used as a feeder has good surface smoothness and excellent strength properties such as tensile strength without deteriorating the optical properties of paper, It can be used for various purposes without limitation. Examples of the paper include various types of paper such as a paper for a pottery, a newspaper, a cloth or a heavy paper, an electrophotographic transfer paper, an inkjet paper, a thermal paper, a pressure sensitive paper, a kraft paper, A paper for impregnation, a paper for impregnation, and a coarse paper. Among them, in one aspect, the paper of the present invention is suitable as a printing paper provided for various printing methods such as offset printing and gravure printing.

Specific examples of the paper in which the hard calcium carbonate of the present invention is internally packed will be described in detail below as non-known paper, coated paper and coated paper, and transfer paper for electrophotography. The paper of the present invention is not limited to these uses.

(Not shown)

The basis weight of the non-known inorganic filler charged with the light calcium carbonate of the present invention is not particularly limited, but the desired effect is exhibited in the range of about 30 to 650 g / m 2. In one embodiment, the basis weight of the present invention is about 35 to 200 g / m 2, and may be about 40 to 120 g / m 2. The light calcium carbonate of the present invention can also be added to thick paper such as cardboard, card, etc., having a thickness exceeding this range.

Examples of the pulp of grassland raw material include bleaching chemical pulp such as LBKP and NBKP generally used, microcircular pulp such as LUKP and NUKP, groundwood pulp (GP), pressed wood pulp (PGW), refiner crumb pulp (RGP) , Thermo-chemical mechanical pulp (TMP), dehydrated pulp (DIP), and waste paper are appropriately mixed and used. Further, one or more kinds of pulp fibers, synthetic pulp, and inorganic fibers obtained from non-wood fiber raw materials such as kenaf can be blended in the raw paper. The mechanical pulp or the DIP can be bleached as required or the degree of bleaching can be arbitrarily selected.

The rosetta type hard calcium carbonate of the present invention can be used in a wide variety of fields such as general used calcium carbonate such as heavy calcium carbonate, light calcium carbonate, calcium sulfite, gypsum, talc, kaolin, engineered kaolin, calcined kaolin, white carbon, amorphous Inorganic particles such as silica, di-laminated kaolin, diatomaceous earth, magnesium carbonate, titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, paper sludge and recrystallized inorganic particles such as recrystallized inorganic particles, urea formalin resin, Resin, urea / formalin resin, melamine resin, styrene / butadiene copolymer resin, phenol resin, plastic hollow particles and the like. The mixing ratio can be adjusted according to the quality of the paper and is not particularly limited, but the effect of the present invention is increased when the rosette type hard calcium carbonate of the present invention is used in an amount of 10 parts by weight or more. In order to obtain a paper having a good yield as a charge, a good size property, a good surface smoothness and a greatly improved paper strength characteristics, the rosette type hard calcium carbonate of the present invention is contained in an amount of not less than 50 parts by weight , More preferably at least 60 parts by weight, and particularly preferably at least 70 parts by weight.

In the case of less than 5% by weight of ash in paper, the optical properties of the paper tend to become insufficient, mainly in whiteness and opacity. Therefore, the ash content of the paper of the present invention is preferably 5% by weight or more, more preferably 10% More preferable. On the other hand, if the ash content exceeds 30% by weight, problems such as wire abrasion and contamination in the paper machine system are liable to occur. Therefore, in general, it is preferable to add a feedstock in a range of 5 to 30% by weight, and it is particularly preferable to add the feedstock in a range of 5 to 20% by weight.

In addition to the pulp and charge as the paper stock, it is also possible to use other additives such as an internal sizing agent, an anionic, a nonionic, a cationic or a positive yield improving agent, a water fountain enhancer, an oil strengthening agent, a dye, a fluorescent dye, And the like can be used as needed. Specific examples of the internal sizing agent include alkylketene dimer, alkenyl succinic anhydride, styrene-acrylic, higher fatty acid, petroleum resin sizing agent, rosin sizing agent and the like. Specific examples of the yield improving agent, water softening agent and soil strength enhancing agent include polyvalent metal compounds such as aluminum (specifically, sulfate bands, aluminum chloride, sodium aluminate, basic aluminum compounds, etc.), various types of cellulosic nanofibers, Cellulose derivatives such as carboxymethyl cellulose, hydroxyethyl cellulose and methyl cellulose, polyacrylamide, urea resin, polyamide-polyamine resin, polyethyleneimine, polyamine, polyvinyl alcohol, polyethylene oxide and the like. The paper entrapped with the rosetta type hard calcium carbonate of the present invention is excellent in size development because of high efficiency of addition of chemicals as described above.

When the pulp feedstock containing the rosetta-type hard calcium carbonate of the present invention is added to the pulp feedstock, it is preferable to add the feedstock while thoroughly stirring the pulp feedstock. Examples of the feedstock include a machine chest inlet and a fan pump inlet.

The paper making conditions are not particularly limited. Examples of the paper making machine include commercially available paper making machines such as a large-sized paper machine, a twin-wire paper machine, a on-top paper machine, a grinding machine paper machine, And the like.

As a papermaking method, any of an acidic grassland, a neutral grassland, a weak alkaline grassland or the like can be used, but since calcium carbonate is dissolved in an acidic region, it is preferable that the grassland is padded in a range of neutral to weakly alkaline.

A surface treatment agent may be applied to paper in order to improve the surface strength, provide water resistance, improve ink deposition and the like, and the like. There are no particular limitations on the type of surface treatment agent, but there are no particular limitations on the type of surface treatment agent, but it is possible to use a starch, such as starch powder, oxidized starch, esterified starch, cationized starch, acetylated tapioca starch as a raw material and produced by thermochemical denaturation or enzyme denaturation in a paper mill Of starch, aldehyde starch, hydroxyethylated starch, and the like. Cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, methylcellulose and cellulose nanofibers, modified alcohols such as polyacrylamide, polyvinyl alcohol, carboxyl-modified polyvinyl alcohol and acetacetylated polyvinyl alcohol, styrene-butadiene-based Polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, polyacrylic ester, or the like may be used in combination. For the purpose of increasing the size, it is also possible to use a surface sizing agent such as a styrene sizing agent, an olefin sizing agent, an acrylate sizing agent, a styrene-acrylic sizing agent, and a cationic sizing agent. In the present invention, various auxiliaries incorporated in a usual clear coating such as a dispersant, a thickener, a repairing agent, a defoaming agent, a water resistance agent, a coloring agent, and a conductive agent are suitably used in the present invention.

As the apparatus for applying the surface treatment coating liquid, a known size press apparatus, for example, a 2-roll type, a 3-roll type, a gate roll type, a film transfer type, or the like can be used. The film transfer type is a method in which a coating film in a wet state is formed on an applicator roll and the coating film is transferred onto a base surface, and examples thereof include a transfer roll coater and a rod metering size press coater. Further, it may be coated using a coater (coating machine) such as a curtain coater, a spray coater, or a blade coater.

It is also possible to apply the surface-treated coating liquid to the paper in an amount of 0.1 to 5.0 g / m < 2 > per one side of the surface with these coating apparatuses and then dry them with a dryer to finish. However, calenders such as a machine calendar, Device. The surface treatment liquid may be applied to both surfaces.

(Coated paper and coated paper)

The paper filled with the hard calcium carbonate of the present invention may be a coated paper having at least one coating layer composed mainly of a pigment and an adhesive. Since the interlaminar strength is improved by incorporating the light calcium carbonate of the present invention, a coated paper excellent in blister suitability and good dimensional stability can be obtained.

Normally, a coating liquid containing a surface treatment agent may be applied to a paper filled with the hard calcium carbonate described above to prepare a coated paper. By performing this surface treatment, it is possible to improve the surface strength of the coated paper or to clean foreign matters on the surface of the coated paper, and it is possible to suppress the occurrence of streaks and the like. However, in the case of an on-machine coater in which a coated layer is coated and dried with a coating layer mainly composed of a pigment and an adhesive, the surface treatment is omitted in order to avoid the limitation of the drying ability and the risk of the splitting There are also cases.

The coating material may be subjected to a smoothing finish treatment by a machine calendar, a soft calendar or the like.

The pigment used in the coating layer is not particularly limited and may be a pigment used in the field of general coated paper such as heavy calcium carbonate, the present invention or other hard calcium carbonate, calcium sulfite, gypsum, talc, kaolin, Inorganic particles such as kaolin, calcined kaolin, white carbon, amorphous silica, demineralized kaolin, diatomaceous earth, magnesium carbonate, titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, paper sludge, Organic resin materials such as urea formalin resin, urea resin, urethane resin, urea formalin resin, vinyl chloride resin, polystyrene resin, urea / formalin resin, melamine resin, styrene / butadiene copolymer resin, phenol resin and plastic hollow particles. And can be appropriately selected and used in combination. The mixing ratio can be adjusted according to the quality of the paper, and is not particularly limited.

As the adhesive for the pigment coating solution, an adhesive used in the field of general coated paper and various surface treating agents used as the surface treating agent in the above-mentioned non-known paper may be used as an adhesive. These adhesives may be used alone or in combination of two or more.

The blending amount of the adhesive is not particularly limited, but is 1 to 50 parts by weight, preferably 5 to 30 parts by weight, per 100 parts by weight of the pigment.

If necessary, various auxiliaries such as a coloring matter, a coloring pigment, a fluorescent brightening dye, a thickening agent, a repairing agent, an antioxidant, an antioxidant, a conductivity inducing agent, a defoaming agent, a UV absorber, a dispersing agent, a pH adjusting agent, a releasing agent, And can be appropriately compounded.

The solid content concentration of the pigment coating liquid can be selected from the range of 25 to 80 mass%. Considering adjustment of coating amount and operability, a range of 50 to 70 mass% is preferable.

The coating layer to be provided on the coated paper is not particularly limited as long as it is a single layer or a multilayer of two or more layers. In the case of multiple layers, it is not necessary that they all be the same, and it is possible to adjust them appropriately according to the required quality level. Also, the coating amount of the coating layer is not particularly limited, and can be adjusted depending on the quality of the white paper of the coated paper, the printing quality, etc., but is generally about 0.5 to 40.0 g / m 2 per one side.

The coating method for providing the coating layer in the present invention may be various coating methods used in the field of ordinary coated paper such as air knife coater, various blade coater, gate roll coater, roll coater, die coater, A curtain coater, a spray coater, or the like can be suitably used.

After the pigment coating liquid is applied to the paper, the coated layer is dried to obtain a coated paper. As the drying method, a usual method such as a steam heating heater, a gas heater, an infrared heater, an electric heater, a hot air heating heater, a microwave, and a cylinder dryer can be arbitrarily selected and used.

The coated paper thus obtained may be subjected to a product treatment by passing paper through various known finishing devices such as a supercalender, a gauge calender, a soft calender, and a mat calender.

(Electrophotographic transfer paper)

An electrophotographic transfer paper can be produced by using a paper impregnated with a specific hard calcium carbonate of the present invention. By internally filling the hard calcium carbonate of the present invention, the correlation strength is improved, so that it is possible to obtain an electrophotographic transfer paper which is less likely to cause curling or paper dust at the time of printing. Further, since hard calcium carbonate of the present invention is hard to abrade the wire of the paper machine, it can be used for grass paper using general paper machine. Particularly, a paper machine used for irritating electrophotographic transfer paper is preferably a hybrid former having a double-sided dehydrating mechanism, a top-top former, and the like, but is not limited thereto.

The pulp raw material of the electrophotographic transfer paper produced in the present invention is not particularly limited, and any pulp raw material generally used as a papermaking raw material may be used, such as various types of pulp exemplified as unprecedented examples. Among them, the use of deinking pulp is preferable in terms of environment.

The light calcium carbonate of the present invention can be used singly or in combination with other paper making charge. In the case of using in combination with other papers for paper making, it is possible to use the known papers which are exemplified as non-papers, singly or suitably in combination of two or more kinds. In order to reduce the curl and the stiffness at the time of printing and to suppress the wire wear at the time of frying, the specific hard calcium carbonate of the present invention is added in an amount of 50 By weight or more, more preferably 60 parts by weight or more, particularly preferably 70 parts by weight or more.

In the case of less than 5% by weight of the ash in paper, the optical characteristics of the paper, mainly whiteness and opacity tend to become insufficient. Therefore, it is preferably 5% by weight or more, more preferably 10% by weight or more. On the other hand, if the ash content exceeds 30% by weight, problems such as the transportability (double feeding, jam trouble, etc.) in the electrophotographic printing machine caused by wire abrasion, contamination in the paper machine system and lowered bending stiffness, . Therefore, in general, the amount is preferably added in the range of 5 to 30 wt%, and particularly preferably in the range of 5 to 20 wt%.

In the case of producing an electrophotographic transfer paper in which the hard calcium carbonate of the present invention is internally packed, one kind or two kinds or more of various kinds of poultice drugs and preparations as exemplified by the above-mentioned non-conventional ones can be used in combination. These formulations may be added to the slurry of the hard calcium carbonate of the present invention in advance and then used in a paper machine, or may be applied to the slurry of the hard calcium carbonate of the present invention and the paper machine separately. Also in the case of electrophotographic transfer paper, since the high drug addition efficiency can be obtained as in the above-mentioned case, the size development is excellent.

For the purpose of enhancing the surface strength, the surface treatment agent may be coated on the electrophotographic transfer paper in which the specific hard calcium carbonate of the present invention is internally filled. As the surface treatment agent, the surface treatment agent exemplified above as the non-known agent may be used. In addition, in order to control the electrical resistance and improve the toner fixability, it is preferable to add an inorganic conductive agent such as sodium chloride, sodium sulfate, potassium chloride or the like, or an organic conductive agent such as dimethylaminoethyl methacrylate as the conductive agent, desirable. The application amount of the surface treatment agent containing a conductive agent is suitably adjusted, but the usual application amount is about 0.5 to 4.0 g / m 2 on both surfaces. The application amount of the conductive agent is about 0.02 to 0.5 g / m 2 on both sides.

The basis weight of the electrophotographic transfer paper of the present invention may be, for example, 40 to 80 g / m < 2 >, and the physical properties may be adjusted to a level having a coefficient of friction or the like of a normal electrophotographic transfer paper.

Example

Hereinafter, the present invention will be described concretely with reference to examples, but the present invention is not limited thereto. In the present specification, "% " is all "% by weight " unless otherwise stated.

Assessment Methods

Each item was evaluated by the following evaluation method.

(1) Average particle size: Using a laser diffraction / scattering particle size analyzer (Masterbinder, Mastersizer 2000), the 50% point (D50) of the volume cumulative distribution was taken as the average particle size.

(2) BET specific surface area: Measurement was carried out in accordance with JIS Z 8830-2001.

(3) Basis weight: Measured according to JIS P 8124.

(4) Paper thickness: Measured according to JIS P 8118.

(5) Density: Determined from basis weight and paper thickness according to JIS P 8118.

(6) Tensile strength: Measured according to JIS P 8113.

(7) Tearing length: Measured according to JIS P 8113.

(8) Bending stiffness: Measured according to JIS P 8125.

(9) Interlaminar peel strength: Measured using an internal bond tester (Kumagai Rikiko Co., Ltd.) in accordance with TAPPI T 569.

(10) Steki Hit size: Measured according to JIS P 8122.

(11) Ash: According to JIS-P8251, the ashing temperature was 525 캜.

Light calcium carbonate aggregate

Hard calcium carbonate having the following form was synthesized by adjusting the temperature and stirring conditions in the reaction at the carbonic acid gas method, and using these hard calcium carbonate, paper was produced. 1 shows an electron micrograph of calcium carbonate 5 in the following table.

Experiment 1: Unpublished  Manufacturing (water base)

The slurry obtained by mixing 75% of the light chlorinated chain pulp (LBKP) with the standard Canadian Standard Freeness (CSF) of 500 mL and 25% of the softwood chain kraft pulp (NBKP) prepared by adjusting the CSF to 475 mL, 0.7% of cationized starch, 2.0% of aluminum sulfate and 0.5% of a neutral rosin sizing agent were added in this order, and the hard calcium carbonate 1 to 4 was added so that the ash content in the paper was about 10 to 28%. After diluting the pulp slurry, the yield improver was added in an amount of 100 ppm per 100 pulp weight of the pulp.

Using this stock material, a square sheet machine was used for several seconds to obtain a sheet having a basis weight of 64 g / m < 2 >. After press dewatering, the sheet was dried at 110 DEG C by a cylinder dryer, and processed to have a paper thickness of 90 mu m by manual cold calendering.

(Reference Example 1)

As a reference example, paper is manufactured using calcium carbonate (calcium carbonate 4: small specific surface area as compared with rosetta type calcium carbonate having an equivalent particle size) in which needle-shaped primary particles aggregate to form secondary particles did. 0.8% of cationized starch, 0.5% of aluminum sulfate, and 0.1% of alkylketene dimer were added in succession to the slurry of 100% of the light chlorinated chain pulp prepared by adjusting the Canadian standard freeness to 450 mL, (Average particle diameter: 7.0 mu m, BET specific surface area: 7.9 m < 2 > / g) so as to be 12.0%. After diluting the pulp slurry, the yield improving agent was added in an amount of 0.1% per weight of the pulp dry weight to obtain a sheet having a basis weight of 60 g / m < 2 > After the start of the press, drying was carried out at 110 占 폚 with a cylinder dryer, and the paper was processed to have a paper thickness of 90 占 퐉 by manual cold calendering.

The results are shown in the following table. However, the starches of Examples 1 and 2 were higher in streaky heat size and hot end length in the equivalent batch as compared with Comparative Example 1. In addition, when the ash content was increased, the rosette type hard calcium carbonate of the present invention also maintained a high stoichiometric size and a hot end length.

Experiment 2: Unpublished  Manufacturing

(High-quality paper 1: basis weight 64g / ㎡)

To the pulp slurry consisting of 91% of light chlorinated chain pulp (LBKP, CSF: 360 mL) and 9% of light chlorinated chain pulp (NBKP, CSF: 500 mL) was added 0.5% of aluminum sulfate, 0.9% of alkylketene dimer sizing agent, 0.08% of alkylketene dimer sizing agent, and 18 ~ 23% of ash in paper, 0.1 ~ 0.1% of 0.1% did.

The paper layer was formed from the above-mentioned materials at a speed of 560 m / min per operation at a speed of operation of 560 m / min, and after surface water treatment and drying, a surface treatment agent consisting of 8.3% of starch and 0.24% of surface size to obtain 0.85 g / Was applied on both sides and smoothed with a machine nip of 1 nip to obtain a paper having a basis weight of about 65 g / m 2.

The results are shown in Table 3. In Example 3 and Comparative Example 2, although Example 3-1 had higher batches than Comparative Examples 2-1 and 2-2, the stitch heat size, tensile strength, The interlaminar peeling strength was excellent. Further, as shown in Examples 3-2 and 3-3, the decrease in the viscosity of the stitchy hits was slight even when the ash content was increased.

(Phase 2: about 81 g / m 2)

To the pulp slurry consisting of 95% of light chain chopped kraft pulp (LBKP, CSF: 300 mL) and 5% of light chlorinated kraft pulp (NBKP, CSF: 460 to 500 mL), 0.9% Rosette type hard calcium carbonate 7 to 8 was added so that the total amount of the starch was 0.9%, the alkylketene dimer size 0.08% and the ash content in the paper was about 18 to 23%, and 0.1% and 0.1% .

The surface treatment agent consisting of 8.0 wt% of starch and 0.200 wt% of the surface treatment agent was applied so as to have a solid content of 1.0 g / m < 2 > And smoothed with a machine calender to obtain a paper sheet having a basis weight of about 81 g / m 2.

As is apparent from the comparison between Example 4 and Comparative Example 3, Example 4-1 is superior to Comparative Example 3 in terms of stiffness size, tensile strength and interlaminar peeling strength in spite of the high ash content, As shown in Examples 4-2 and 4-3, when the ash content was multiplied, the streaky heat-sizing degree and the interlaminar peeling strength were higher than those of Comparative Example 3.

Experiment 3: Unpublished  Manufacturing (Newspaper)

The slurry was mixed with 80% of pulp (DIP, CSF: 220 mL), 15% of mechanical pulp (MP, CSF: 70 mL) and 5% of softwood kraft pulp (NBKP, CSF: 520 mL) 2.0% of aluminum sulfate was added, and rosety-type hard calcium carbonate 11 to 14 was added so that the ash content in the paper was about 18%. The pulp slurry was diluted to 0.5%, and 100 ppm of the yield improving agent per 100 ppm of the pulp weight was added to form a stock.

Using this stock material, a few seconds were carried out with a round sheet machine to obtain a sheet having a basis weight of 43 g / m 2. After the press was started, it was dried at 120 캜 by a cylinder dryer.

The results are shown in the following table, but the papers of Examples 5, 6, and 7 were tensile strengths and bending stiffnesses equal to or higher than those of Comparative Example 4, even though the ash content was higher than that of Comparative Example 4. [

Experiment 4: Coated  Produce

A pulp slurry consisting of 86% of light chain chalk pulp (LBKP, CSF: 350 mL), 8% of light chain chalk kraft pulp (NBKP, CSF: 600 mL) and 6% of highland pulp (DIP, CSF: 240 mL) 9 to 10 parts of hard calcium carbonate were added to the total solid content so that the amount of aluminum sulfate was 0.9%, that of MK was 0.4%, that of the emulsifier was 0.3%, and that in the paper was about 15 to 17%, and 80 ppm of yield was added, did.

The ground layer was formed at a speed of 910 meters per minute per minute using a long-distance papermaking machine from the above-mentioned materials, and after grounding, drying, and smoothing with a machine calender of 2 nip, 54.5 g / m 2 of raw paper was obtained.

Into this pigment, a pigment slurry consisting of 70 parts of hard calcium carbonate and 30 parts of heavy calcium carbonate was mixed with 100 parts of pigment, 4 parts of starch, 8 parts of latex, and a coating material and dye added thereto, so that the coating amount was 10.5 g / Coated on both sides and dried to obtain a coated paper having a basis weight of 75.5 g / m < 2 >.

The results are shown in the following table, but the coated paper of Example 8 exhibits a high thermal end length and an interlaminar peel strength even with ash as equal to or higher than that of Comparative Example 5, and also has excellent smoothness and gloss Therefore, it is considered that the printing property is also excellent.

Claims (6)

Wherein the rosetta type hard calcium carbonate has a BET specific surface area of 1.0 to 8.0 m < 2 > / g and an average particle diameter (D50) of 3.0 to 15.0 m . The method according to claim 1,
Wherein the Rosetta type hard calcium carbonate has a BET specific surface area of 3.0 m < 2 > / g or more. 3. The method according to claim 1 or 2,
Wherein the rosette type hard calcium carbonate has an average particle size (D50) of 3.5 탆 or more. 4. The method according to any one of claims 1 to 3,
Paper having a by-product in the paper of 10% by weight or more. 5. The method according to any one of claims 1 to 4,
Wherein at least 10% by weight of the logotype is rosetta type hard calcium carbonate. 6. The method according to any one of claims 1 to 5,
Non-known paper having no pigment coating layer.

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