WO2007142302A1

WO2007142302A1 - Cast-coated paper

Info

Publication number: WO2007142302A1
Application number: PCT/JP2007/061563
Authority: WO
Inventors: Hiroshi Koyamoyo; Koji Kutsuwa; Masashi Okamoto; Hidehiko Kai; Koji Okomori; Takashi Ochi; Noriyuki Ishibashi; Nobumasa Hayashi
Original assignee: Nippon Paper Industries Co., Ltd.; Nippon Paper Crecia Co., Ltd.
Priority date: 2006-06-07
Filing date: 2007-06-07
Publication date: 2007-12-13
Also published as: CN101490338B; EP2042656A1; US20120043372A1; CN101490338A; EP2042656A4

Abstract

A cast-coated paper which is excellent in coated-paper quality and printability and functions to decompose a harmful substance upon irradiation with light. The cast-coated paper is obtained by forming on a raw paper a cast coating layer comprising a pigment and an adhesive as major components and pressing the cast coating layer in a wet state against a heated mirror surface of a drum to dry and finish the layer. The cast-coated paper is characterized in that the cast coating layer contains titanium oxide having an average secondary-particle diameter of 300-2,000 nm in an amount of 1-30 parts by weight per 100 parts by weight of the pigment and the titanium oxide has been treated beforehand by mixing it with a silica sol or alumina sol in a [titanium oxide]/[silica sol or alumina sol] proportion of from 2/1 to 1/2.

Description

Specification

Cast coated paper

Technical field

[0001] The present invention relates to a cast coated paper having good printability because it maintains excellent coating suitability and an appropriate coefficient of friction, and also has an excellent air cleaning effect.

Background art

[0002] Titanium oxide is attracting attention as the demand for removing harmful substances in daily life such as offensive odors has increased with increasing interest in the living environment. Titanium oxide has traditionally been used as a pigment with excellent opacity and whiteness for papermaking, but fine titanium oxide uses light energy to cause an oxidation-reduction reaction, and to eliminate various harmful substances in the air. It is known to break down, and development is underway to carry it on paper to take advantage of this phenomenon. For example, a photocatalytic paper in which a water-soluble polymer and a substance having a photocatalytic action such as titanium oxide are internally added to paper has been disclosed (see Patent Document 1). In order to demonstrate this, the method of having a photocatalytic substance inside the paper layer is not efficient, but is not sufficient. In addition, the print quality when printed in color, such as ink fillability, printing gloss, and sharpness of printed matter, is not sufficient. In addition, a printed sheet is disclosed in which a titanium oxide fine powder is bonded to an inorganic binder such as silica sol and a coating in which the surroundings are bonded with an organic adhesive is applied (see Patent Documents 2 and 3). However, when a titanium oxide / silica sol mixed coating was applied, the viscosity of the coating having a small particle size of titanium oxide and silica sol significantly increased, and the coating suitability was poor. In addition, the coverage with the coating was insufficient, and there were problems of poor quality such as high blank paper glossiness, printing glossiness, printing surface feeling, and surface strength. Furthermore, as general printing paper, non-coated paper, finely coated paper, high-quality coated paper, etc. are used in the text of inserts, magazines, catalogs, etc., even if the paper is given a photocatalytic effect. However, the photocatalytic effect was not sufficiently exhibited with few opportunities for use in an environment exposed to light. On the other hand, cast coated paper characterized by high white paper glossiness and printing glossiness is preferred for use in photocatalytic paper, such as magazine covers and posters, and should be used in an environment with sufficient exposure to light. There has been a demand for a cast coated paper imparted with a large photocatalytic effect. However, when photocatalytic titanium oxide is simply used in the conventional formulation and manufacturing method, it is difficult to obtain operability due to changes in paint properties, reduced productivity, sufficient white paper gloss, and excellent print quality. It was difficult to produce cast coated paper with excellent air cleaning effect.

Patent Document 1: JP-A-10-226983

Patent Document 2: JP 2000-129595 A

Patent Document 3: Japanese Patent Laid-Open No. 11-117196

Disclosure of the invention

Problems to be solved by the invention

[0003] In view of such circumstances, an object of the present invention is to provide a cast coated paper that has excellent coated paper quality and printability, and also has an action of decomposing harmful substances when exposed to light. There is to serve.

Means for solving the problem

As a result of earnest research on the above problems, the present inventors have provided a cast coating layer mainly composed of a pigment and an adhesive on the base paper, and heated the cast coating layer in a wet state. In cast coated paper that is pressed onto the drum surface and dried to finish, the cast coating layer contains titanium oxide with an average secondary particle size of 300 nm to 2000 nm per 100 parts by weight of pigment:! To 30 parts by weight As a result, it has been found that cast coated paper can be obtained that has a high printing glossiness of the printed matter, a good printing surface feeling, etc., and also has the action of decomposing harmful substances and odor components when exposed to light. It was. In addition, by blending 5 to 40 parts by weight of an organic adhesive with respect to 100 parts by weight of the pigment in the cast coating layer, 50% by weight or more of the organic adhesive is used as a copolymer latex. It is possible to obtain a more balanced print quality such as workability, excellent printing gloss, printing surface feel, and surface strength, and a photocatalytic effect. The copolymer latex preferably has a glass transition temperature of 120 to 40 ° C. In the present invention, the titanium oxide is mixed with silica sol or alumina sol, and the titanium oxide: silica sol or alumina sol is mixed at a mixing ratio of 2: 1 to 1: 2, so that the deterioration of the paper due to the photocatalytic decomposition reaction, It is possible to produce cast coated paper that further suppresses deterioration in print quality due to decomposition or the like and has good printability. The invention's effect

[0005] According to the present invention, it has a high white paper glossiness peculiar to cast coated paper, good printing quality such as printing glossiness, printing surface feeling, surface strength, etc., and is good because it maintains an appropriate coefficient of friction. It is possible to obtain cast coated paper that has good printability and also has the effect of decomposing harmful substances when exposed to light.

BEST MODE FOR CARRYING OUT THE INVENTION

[0006] In the present invention, in order to impart an air cleaning effect to cast coated paper, a part of the pigment blended in the coating liquid has fine particles having a photocatalytic performance with an average secondary particle diameter of 300 to 2000 nm. It is important to use titanium oxide at a specific blending ratio, preferably 500-1500 nm, more preferably 700-1300 nm. Titanium oxide itself has photocatalytic performance regardless of particle size. If the average particle size of the secondary particles is less than 300 nm, the dispersibility of the titanium oxide slurry decreases and the viscosity of the paint becomes extremely high, resulting in a decrease in productivity and print quality and printing workability due to lack of titanium oxide. , The photocatalytic function decreases. On the other hand, when the average particle diameter of the secondary particles exceeds 2000 nm, the smoothness of the coated paper is lowered and the printing quality is lowered. The primary particle size of titanium oxide is preferably 5 to 100 nm, more preferably 10 to 50 nm, and still more preferably 10 to 35 nm. If the primary particle size is less than 5 nm, the dispersibility of the titanium oxide slurry and the fluidity of the paint will decrease, and the print quality and workability will tend to be poor. If it exceeds lOOnm, the surface area becomes small, so photocatalytic performance tends to be insufficient.

[0007] Fine titanium oxide can have the ability to decompose harmful substances in the air when exposed to light. The compounding ratio of titanium oxide is 1 to 30 parts by weight out of 100 parts by weight of the pigment, preferably 5 to 25 parts by weight, and more preferably 5 to 20 parts by weight. Titanium oxide compounding rate Force If the amount is less than 1 part by weight, the amount of photocatalyst is too small to obtain a sufficient air cleaning effect. In the present invention, it is important to use fine titanium oxide having a high photocatalytic effect. However, the fine titanium oxide has a very low slurry concentration when slurried for use in paints having very poor fluidity. Become. Therefore, when blended in an amount exceeding 30 parts by weight, an air cleaning effect can be obtained, but the coating concentration is greatly reduced, making it difficult to apply a coating amount of a certain value or more. With the amount of coating applied with cast coated paper When compared, it is difficult to obtain a high glossiness of a blank paper, and the printing surface feeling, surface strength, and resistance to chilling are inferior. The anti-chalking aptitude means the resistance to powder falling due to photodegradation and deterioration of the coating layer surface and the base paper layer after light irradiation. In addition to titanium oxide, titanium oxide in the present invention includes all titanium oxides or hydroxides called hydrous titanium oxide, hydrated titanium oxide, metatitanic acid, orthotitanic acid, and titanium hydroxide. Can be manufactured. In addition to an ultraviolet light responsive photocatalyst generally used as a photocatalyst, a visible light responsive photocatalyst that responds to light in the visible light region and exhibits a photocatalytic effect can also be used. The titanium oxide used in the present invention preferably has a specific surface area of 10 to 350 m ² Zg. In addition, the titanium oxide of the present invention mixes silica sol or alumina zonole with titanium oxide, so that the surrounding of fine titanium oxide is coated with silica zonole or alumina sol having an inorganic adhesion function. It is possible to further suppress a decrease in print quality due to component decomposition and the like. The mixing ratio of titanium oxide and silica sol or alumina sol inorganic adhesive is in the range of 5 ::! To 1: 5 in the polymerization ratio, and the range of 2: 1 to 1: 2 in the polymerization ratio is preferred. More preferably, it is 2: 1 to: 1: 1.5. If the ratio of titanium oxide is higher than 5: 1, it tends to cause deterioration of the paper due to decomposition of the organic adhesive and pulp fibers in the paint, or deterioration of print quality due to decomposition of the ink components of the printed matter. If the ratio of titanium oxide is too lower than 1: 5, the coefficient of static friction of the paper will increase significantly, causing paper jam problems due to double feeding during printing, and the printing workability tends to be inferior. Moreover, it is preferable to use a silica sol from the point of light transmittance. When preparing the coating liquid, in order to efficiently coat the surroundings of fine titanium oxide, titanium oxide and silica or colloidal solution of alumina are mixed at a certain ratio, stirred for a certain period of time, and then other pigments and auxiliaries are added. It is preferable to add it. Further, in the present invention, a mixture of silica sol and alumina sol inorganic adhesive can be mixed with titanium oxide.

When cast coated paper is used in a carton, it has a high white paper gloss and is capable of producing a high-quality thin paper carton. During carton processing, the surface of the cast coated paper is rubbed and scratched. Problems may occur. In this case, it is preferable to contain 5 parts by weight or more of the above-mentioned silica zonole with respect to 100 parts by weight of the pigment, and more preferably 5 to 50 parts by weight improves the scratch on the thin paper carton. This is the final product thin leaf It is important for enhancing the cosmetics of the paper box. In addition, with regard to cartons, from the viewpoint of preventing deterioration of paper and printing quality, or from the viewpoint of printing workability, the mixing ratio of titanium oxide and silica sol or alumina sol inorganic adhesive is 5 ::! ~ The ratio is in the range of 1: 5, and the polymerization ratio is more preferably in the range of 2: 1 :! to 1: 2 and more preferably 2: 1 to 1: 1.5.

[0009] In the present invention, other pigments provided in the cast coating layer include kaolin, clay, delaminated clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, which are conventionally used in coated paper production. Inorganic pigments such as barium sulfate, calcium sulfate, zinc oxide, caustic acid, silicate, colloidal silica, and satin white, and organic pigments such as plastic pigment can be selected and used as necessary. In the present invention, it is preferable to use kaolin in terms of the photocatalytic effect, white paper surface feeling, and white paper glossiness, and the blending amount is preferably 10 parts by weight or more per 100 parts by weight of the pigment. More preferably, it is 40 parts by weight or more.

In the present invention, the organic adhesive is 5 to 40 parts by weight, preferably 8 to 40 parts by weight, more preferably 8 to 30 parts by weight, particularly preferably 100 parts by weight of the pigment in the cast coating layer. Is to blend 10-20 parts by weight. When the organic adhesive is less than 5 parts by weight, sufficient surface strength cannot be obtained, and the carton cacheability tends to be inferior. On the other hand, when the amount exceeds 40 parts by weight, the coating concentration decreases, it becomes difficult to control the coating amount, the drying load increases, the coating speed decreases, and the titanium oxide is used as an adhesive. It is not preferable because it has a disadvantage that the air cleaning effect is reduced. In view of the air cleaning effect, it is preferable that the number of blended parts of the organic adhesive is small. As adhesives of the present invention, styrene-butadiene-based, styrene-acrylic, ethylene-vinyl acetate-based, butadiene-methyl methacrylate, and butyl acetate butyl acrylate are conventionally used for coated paper. Synthetic adhesives such as polybutyl alcohol, maleic anhydride copolymer, acrylic acid 'methyl metatalylate copolymer, casein, soy protein, synthetic protein Proteins, oxidized starches, positive starches, etherified starches such as urea phosphate esterified starch, hydroxyethyl etherified starch, starches such as dextrin, carboxy ethenoresenorelose, hydroxyethinoresenorelose or hydroxymethinolol One or more organic adhesives such as cellulose derivative adhesives such as senorelose are appropriately selected and used. Force to be included Among the total organic adhesives, the copolymer latex is preferably contained in an amount of 50 to 90% by weight, more preferably 60 to 90% by weight, more preferably 60 to 90% by weight. When the copolymer latex is less than 50% by weight, the photocatalytic effect tends to decrease because it is difficult to obtain the high white paper gloss characteristic of cast coated paper. Also, if it exceeds 90% by weight, stickiness to the cast drum will occur and productivity will be reduced. The copolymer latex used is preferably a copolymer latex having a glass transition temperature of -20 to 40 ° C, more preferably -20 to 30 ° C, and even more preferably -10 to 30 ° C. When the glass transition temperature exceeds 40 ° C, it is difficult to obtain a surface strength sufficient for printing. Further, when the glass transition temperature is less than −20 ° C., the photocatalytic effect tends to be insufficient, and the operability tends to decrease due to stickiness to a roll such as a cast drum. For core-shell type copolymer latex with different glass transition temperatures in the particles, it is preferable that the glass transition temperature of the shell layer (surface layer) falls within the above temperature range. The glass transition temperature of the inner layer is preferably lower than that of the shell layer (surface layer). The particle size of the copolymer latex is preferably 50 to 250 nm from the viewpoint of printing quality and surface strength. The water-soluble polymer adhesive such as starch is preferably 10 parts by weight or less.

[0011] In addition to the above pigment and adhesive, the cast coating layer contains sodium chloride, ammonium chloride, zinc chloride, magnesium chloride, sodium sulfate, potassium sulfate, ammonium sulfate, and zinc sulfate. , Magnesium sulfate, ammonium nitrate, monobasic sodium phosphate, ammonium phosphate, calcium phosphate, sodium polyphosphate, sodium hexametaphosphate, sodium formate, ammonium formate, sodium acetate, potassium acetate, sodium monomonophosphate, sodium malonate, Ammonium salts of inorganic and organic acids such as sodium tartrate, potassium tartrate, sodium citrate, sodium citrate, sodium lactate, sodium dalconate, sodium adipate, sodium dioctylsulfosuccinate, metal salts, methylamine The Etano Ruamin, can be used as appropriate diethylenetriamino § Min, various additives such as diisopropylamine. In addition, as necessary auxiliary agents such as dispersants, thickeners, water retention agents, antifoaming agents, colorants, mold release agents, flow modifiers, water resistance agents, preservatives, printability improvers, etc. Various auxiliaries blended in the coating composition for coated paper are appropriately used.

[0012] The base paper for cast coating of the present invention is blended with ordinary pulp, filler and the like. In the present invention The kind of pulp blended in the base paper is not particularly limited. For example, hardwood kraft pulp (hereinafter referred to as LBKP), conifer kraft panolep (hereinafter referred to as NBKP) thermo-mechanical pulp, groundwood pulp, waste paper pulp and the like are used. From the standpoint of print quality, mechanical pulp is preferred to contain 60% by weight or less of the total pulp because it degrades and discolors when exposed to light when used in large amounts. Most preferred is 100% chemical pulp.

[0013] Further, as fillers to be blended in the base paper, known fillers such as heavy calcium carbonate, light calcium carbonate, kaolin, clay, talc, hydrated silicic acid, white carbon, titanium oxide, and synthetic resin filler are used. be able to. The amount of filler used is about:! To 30% by weight, preferably 3 to 20% by weight, per pulp weight. In addition, chemicals usually used in the paper making process, such as paper strength enhancers, sizing agents, antifoaming agents, colorants, softening agents, bulking agents (low density agents), etc., are used as necessary. As long as the effect is not hindered, it can be added to the stock to make paper.

[0014] The paper making method of the base paper is not particularly limited, and any of the base papers made by acid paper making, neutral paper making, or alkaline paper making using a long net machine, top net machine, etc. including a top wire, etc. Of course, medium base paper including mechanical pulp can also be used. Furthermore, for the purpose of improving the surface strength and sizing properties, a surface treatment agent containing a water-soluble polymer as a main component may be applied to the base paper. As the water-soluble polymer, those usually used as surface treatment agents such as oxidized starch, hydroxyethyl etherified starch, enzyme-modified starch, polyacrylamide, and polyvinyl alcohol may be used alone or as a mixture thereof. it can. In addition to the water-soluble polymer, a paper strength enhancer for improving water resistance and improving surface strength and an externally added sizing agent for imparting size can be added to the surface treatment agent. Surface treatment agents are applied by coating machines such as two-roll size press coaters, gate roll coaters, blade metering size press coaters, rod metering size press coaters, and film transfer type roll coaters such as shim sizers. Application power S In the present invention, in addition to the application of the surface treatment agent, the base paper coated with a coating liquid containing a pigment and an adhesive used for general coated paper using the coating machine, or the surface After applying the treatment agent and drying, blade coater, roll coater A base paper coated with a single knife or air knife coater can be used as a base paper for cast coating. Les desirability of about 5 to 30 g / m ² at a coat weight per side by dry weight of the case. Moreover, it is possible to apply one side and both sides according to a use. As a method for drying the wet coating layer, for example, various types of dryers such as the above heating cylinder, heated hot air air dryer, gas heater dryer, electric heater dryer, infrared heater dryer and the like are used alone or in combination. The degree of drying of the coated paper varies depending on the type of base paper, the type of coating composition, etc., and is generally in the range of about 1 to 10% as paper moisture, and is dried in the range of about 2 to 7%. Is desirable. Furthermore, if necessary, the pre-coated base paper can be subjected to a smoothing process such as a super calendar or a soft calendar beforehand.

[0015] The cast coating base paper, a general coated paper, basis weight typically used for coated board it is possible to use 25 ~600g / m ² about coating base paper, when coated paper, preferably Is 50 to 200 g / m ² , and in the case of coated paperboard, 230 to 500 g / m ² force S is preferred.

[0016] As a method for applying a cast coating composition prepared on a base paper, a two-roll size press coater, a gate roll recorder, a blade metering size press coater, and a rod metering size press coater In addition to film transfer type roll coaters such as shim sizers, JF sizers and reverse roll coaters, bladed dip / blade coaters, jet fountain / blade coaters, short dwell time application type coaters, Instead, it can be applied with a well-known coater such as a mouth metering coater using a grooved rod, a plain rod, etc., an air knife coater, a curtain coater or a die coater. 5-30 g / m ² is more preferable Is 10-25 g / m ² . After coating the cast layer, cast finish. Cast finishing methods include a direct method of casting in a wet state, a solidification method in which a wet coating layer is solidified and cast to finish, and a wet coating layer is once dried and then applied with a rewetting liquid. There are rewetting methods in which the work layer is rewet and cast to finish, but the rewetting method is preferred in terms of the photocatalytic effect. Depending on the purpose, one or both sides can be cast. In the cast finish, the surface temperature of the heated mirror drum is preferably 100 ° C or higher. [0017] The effect of the present invention is remarkable in a cast coated paper having a high white paper glossiness of 80% or more, preferably 85 to 98%, according to JIS-P8142. When the glossiness of white paper increases, the coating layer has a dense structure, the contact probability between the photocatalyst blended in the coating layer and harmful components in the air decreases, and the air cleaning effect tends to decrease. However, the production method of the present invention can exhibit an excellent air cleaning effect and high printability even in cast coated paper having high white paper glossiness.

[0018] In the present invention, it is also possible to make a thin paper carton and a thin paper box using the cast coated paper or cast paperboard coated paper.

Next, a method for processing and manufacturing a thin paper carton and a thin paper box using the coated paper as described above will be described.

[0020] The thin paper of the present invention includes sanitary paper such as tissue, toilet paper, paper towels, and table napkins, and wipers made of paper or nonwoven fabric.

[0021] The manufacturing method of the thin paper carton is not particularly limited. For example, it is manufactured by the following method. The printing and processing of white paperboard is outlined in Pagel67 from Pagel53 of the white paperboard 'paper container' published by Paper Industries Times.

[0022] An example of manufacturing a thin paper box from a thin carton base paper (coated paper) will be described. The base paper carton base paper (coated paper) containing a photocatalyst with a basis weight of 230g / m ² to 640g / m ² made by the above method is used to improve the cosmetics when used as a paper paper box for consumers. Print the design, precautions, brand name, quality indication, JAN code, product characteristic appeal, and other indications. Printing can be mainly done by offset printing by lithographic printing, gravure printing by intaglio, etc. In addition, UV printing, Sinolec screen printing by stencil, flexographic printing by letterpress, hot stamping that thermocompresses foil film Can be printed. In hot stamp printing, foil films of gold, silver, etc. are stacked as printing layers.

[0023] The air-cleaning effect and deodorizing effect of the thin paper carton containing the photocatalyst tend to be reduced by the ink layer and the printed layer of the film. The printing area of the thin paper carton is preferably about 80% to 80% per area exposed to light. More preferably, it is:! -50%. If necessary, when manufacturing cartons for thin paper, varnishing and unloading may be carried out. This step can be omitted.

[0024] The intermediate product of the thin paper carton after printing is subjected to a punching process. In the punching process, a punching process, a picking perforation process, and a line punching process for folding a box are performed in the form of a development view of the surface. An embossing treatment may be performed in the punching process for cosmetics.

[0025] Further, the intermediate product of the thin paper carton after the punching process is further bonded with a slitting polyethylene film by a window pasting machine using an acetic acid bule type, EVA type adhesive or the like. Currently, many filmless thin paper boxes have been put on the market due to the environmental problem of waste reduction, and the present invention is also good with this filmless thin paper box.

[0026] Next, an intermediate product of a thin paper carton with or without a film is glued with a sack machine and boxed to produce a thin paper carton. The thin paper carton produced in this way is supplied to the tissue processing process. In tissue processing, supply thin paper cartons with a processing machine called cartoner, stand up thin paper cartons, insert thin tissue such as tissue from the side of thin paper cartons, seal with adhesive, and press-bond. Thus, a thin paper box containing the thin paper can be obtained.

[0027] What is packed in a thin paper box in the present invention is household, commercial, industrial facial tissue, toilet paper, paper towels, table napkins, and other sanitary paper, and paper or non-woven wipers. The form may be a sheet shape such as a V-shaped fold, a C-shaped fold, a Z-shaped fold, or a roll shape. Fig. 1 shows an example of the thin paper box manufactured in this way, and the A, B, C, D, and E surfaces of the thin paper box shown in Fig. 1 (solar light, fluorescent light, light bulbs, etc. are effective) area practical standpoint surface) standpoint force et 400 cm ² force of the air cleaning effect and deodorizing effect, Shi preferred that a et ^2, 000cm 2 les.

[0028] The present invention will be specifically described below with reference to examples, but it should be understood that the present invention is not limited to these examples. Unless otherwise specified, parts and percentages in the examples refer to parts by weight and% by weight, respectively. A test was conducted based on the following evaluation method for producing a thin paper box from a thin carton base paper and a thin carton for cast coated paper.

Example [0029] The present invention will be specifically described below with reference to examples, but it should be understood that the present invention is not limited to these examples. Unless otherwise specified, parts and percentages in the examples refer to parts by weight and% by weight, respectively. The coating liquid and the obtained cast coated paper were tested based on the evaluation method as shown below.

(Evaluation methods)

(1) Titanium oxide particle measurement: calculated from a photograph taken with an electron microscope.

[0030] The fine titanium oxide slurry was thinly applied on the electron microscope data base and dried in a drier set at 40 ° C. Thereafter, the particles were observed and measured with a FE-SEM (field emission scanning electron microscope / JSM-6700F manufactured by Nippon Denshi Co., Ltd.) at an imaging magnification of 10,000. For secondary particles, the average value obtained by measuring 100 particle sizes was taken as the average particle size of secondary particles.

(2) Cast coating operability: When coated paper was cast, it was judged by sticking of the cast coated paper to the cast drum or contamination of the cast drum.

◎ · · · No sticking to the cast drum or dirt on the cast drum

〇… There is almost no sticking to the cast drum or dirt on the cast drum.

△ ... Slight sticking to cast drum or cast drum contamination occurs

X: A cast paper with good quality cannot be produced due to sticking to the cast drum or contamination of the cast drum.

(3) White paper glossiness: 75 in accordance with JIS P 8142: 1998. Gloss was measured.

(4) Blank paper texture: The blank paper texture such as gloss unevenness on the cast coated paper surface was visually evaluated. ◎: Extremely good, ○: Good, △: Slightly inferior, X: Inferior

(5) Surface strength: Using RI-II type printing tester, SMX tack grade 20 (black) ink manufactured by Toyo Ink Co., Ltd. was compared, and the dry pick strength was compared, and the strength was visually evaluated in four stages.

◎: Extremely excellent, ○: Excellent, △: Somewhat problematic, X: Problem

(6) Printing workability: When printing was performed at 8000 sheets Z on a Roland sheet-fed press (R304), the frequency of paper jams due to double feeding was evaluated in four stages.

©: No multi-feed and no paper jam, ○: Slight double-feed was found but no paper jam, △: Multi-feed was seen and some paper jam occurred, X: Multi-feed was seen and paper jam occurred frequently (7) Photocatalytic effect: Evaluated by Photocatalyst Performance Evaluation Test Method IIb “Gas Bag B Method” established by the Photocatalyst Products Technology Council. Acetaldehyde decomposition rate (%) after irradiation with ultraviolet rays for 20 hours was measured and evaluated in four stages according to the decomposition rate.

◎: Very good (decomposition rate: 70./. Or more), ○: Slightly excellent (same: 69-50%), △: Slightly inferior (same: 49%-: 10%), X: Slightly inferior (same as above) : less than 10)

[Example 1]

Fine Titanium Oxide Slurry A (CSB-M; Sakai Chemical Co., Ltd., secondary particle size 20-30nm, secondary particle average particle size lOOOnm) 10 parts (solid content), colloidal silica (Nissan Chemical Co., Ltd. Sno Itex 40) 10 parts were stirred with a serie mixer for 1 hour (titanium oxide: colloidal Siri force mixture ratio = 1: 1). It contains 60 parts of primary kaolin (trade name: UW-90Z Engelhard), 30 parts of light calcium carbonate (TP121 / Okutama Kogyo), and 0.2 part of poly (sodium acrylate) as a dispersant. The pigment slurry dispersed with a serie mixer was added to prepare a pigment slurry having a solid content of 60%. Antifoam (San Nopco 1407 / San Nopco) 0.5 parts, mold release agent (Knob Coat C104 / San Nopco) 5 parts, Styrene-butadiene copolymer latex A (Glass transition temperature—10 ° C, 15 parts of particle diameter 190 nm) and 7 parts of casein were added (latex ratio: 68%), and water was further added to prepare a coating solution having a solid content of 50%. One side was coated with a blade coater on a base paper having a basis weight of 100 g / m ² containing 100 parts of chemical pulp and 12 parts of light calcium carbonate as a filler so that the coating amount was 20 g / m ² and dried. The coated paper thus obtained is rewet on the surface of the coating layer with a rewetting liquid (polyethylene emulsion 0.5% concentration), and then pressed by a forming roll and a cast drum. And then press and dry on a cast drum with a speed of 100 m / min and a surface temperature of 115 ° C, and then release from the cast drum with a strip-off roll to remove the cast coated paper by the re-cast method. Obtained.

[Example 2]

In Example 1, Titanium oxide slurry A 10 parts of coating liquid, 10 parts of colloidal silica, grade 1 kaolin (trade name: UW_90 / manufactured by Engelhard) 60 parts, light calcium carbonate (TP1 21 / made by Okutama Kogyo) 30 parts Instead of 20 parts titanium oxide slurry, 20 parts colloidal silica, 50 parts kaolin (product name: JapanglossZj.M. Huber), light calcium carbonate (TP12 (1 / Okutama Kogyo Co., Ltd.) A cast coated paper was obtained in the same manner as in Example 1 except that the amount was changed to 30 parts.

[Example 3]

In Example 1, 15 parts of styrene-butadiene copolymer latex A (glass transition temperature_10. C, particle diameter 190 nm) and 7 parts of casein (latex ratio: 70%) in the coating liquid were mixed with styrene-butadiene copolymer. A cast coated paper was obtained in the same manner as in Example 1, except that the united latex was changed to 19 parts (latex rate: 100%).

[Example 4]

In Example 1, except that the styrene-butadiene copolymer latex A (glass transition temperature—10 ° C.) was changed to the styrene-butadiene copolymer latex B (glass transition temperature—23 ° C.). Obtained a cast coated paper in the same manner as in Example 1.

[Example 5]

In Example 1, 15 parts of styrene-butadiene copolymer latex A (glass transition temperature—10 ° C., particle size 190 nm) and 7 parts of casein (latex ratio: 70%) in the coating liquid were styrene-butadiene copolymer. Latex A (Glass transition temperature—10 ° C, particle size 190 nm) 6 parts, Casein 12 parts, Polybulal alcohol (trade name; PVA117 / Kuraray) 12 parts (latex rate: 20%) A cast coated paper was obtained in the same manner as in Example 1.

[Example 6]

In Example 1, the cast paint was applied with a reverse roll coater attached to the cast coater so that the coating amount was 20 g / m ² per side, and then coagulated with a calcium formate aqueous solution (10%). The wet coating layer is gelled by contact with the liquid, and the gelled coating layer is passed through a press ep formed by a foamer roll and a cast drum, and the speed is 70 m / min and the surface temperature is 115 ° C. After being pressed against the cast drum and dried, it was released from the cast drum with a strip-off roll to obtain a cast coated paper by a coagulation method.

[Example 7]

In Example 6, instead of 1st grade kaolin (trade name: UW_90 / Engelhard) 60 parts of coating liquid, 30 parts of light calcium carbonate (TP121 / Okutama Kogyo Co., Ltd.) Dokaolin (trade name: Eclipse 650 / Engelhard) 70 parts, Light calcium carbonate (TP121 / Okutama Kogyo) 20 parts Obtained.

[Example 8]

In Example 1, Titanium oxide slurry A 10 parts of coating liquid, 10 parts of colloidal silica, grade 1 kaolin (trade name: UW_90 / manufactured by Engelhard) 60 parts, light calcium carbonate (TP1 21 / made by Okutama Kogyo) 30 parts Instead of titanium oxide slurry 10 parts, colloidal silica 16 parts (titanium oxide: colloidal silica compounding ratio = 1: 1. 6), kaolin (product name: Japanglos sZj.M. Huber) 60 parts, light calcium carbonate (TP121 / Okutama Kogyo Co., Ltd.) Cast coated paper was obtained in the same manner as in Example 1 except that the amount was changed to 30 parts.

[Comparative Example 1]

In Example 1, 10 parts of titanium oxide slurry of coating liquid, 10 parts of colloidal silica, kaolin (trade name: UW-90 / Engelno, manufactured by Dou) 60 parts, light calcium carbonate (TP121 / manufactured by Okutama Industry) Instead of 30 parts, Kaolin (trade name: UW-90 / Engelno, manufactured by Dod) 70 parts, light calcium carbonate (TP121 / Okutama Kogyo) 30 parts, except that it was changed in the same manner as Example 1 A cast coated paper was obtained.

[Comparative Example 2]

In Example 1, 10 parts of titanium oxide slurry of coating liquid, 10 parts of colloidal silica, kaolin (trade name: UW-90 / Engelno, manufactured by Dou) 60 parts, light calcium carbonate (TP121 / manufactured by Okutama Industry) Instead of 30 parts, 40 parts of titanium oxide slurry, 40 parts of colloidal silica, 40 parts of strength (product name: UW-90 / Engelhard), 20 parts of light calcium carbonate (TP121 / Okutama Kogyo) Produced cast coated paper in the same manner as in Example 1.

[Comparative Example 3]

In Example 1, 10 parts of titanium oxide slurry A in the coating liquid was changed to 10 parts of fine titanium oxide slurry B (STR-60N, Sakai Chemical Industry, primary particle diameter 40-50 nm, average particle diameter of secondary particles 25 OOnm) A cast coated paper was obtained in the same manner as in Example 1 except that. The results are shown in Table 1. table 1]

Next, an example of making a carton for thin paper and a box for thin paper using cast coated paper is shown.

[Example 9] Fine Titanium Oxide Slurry A (CSB-M; Sakai Chemical Co., Ltd .; secondary particle size 20-30nm, secondary particle average particle size lOOOnm) 10 parts (solid content), colloidal silica (Nissan Chemical Co., Ltd. Sno-Tex 40) 16 parts were stirred with a serie mixer for 1 hour. Add 1 part kaolin (product name: UW-90Z Engelhard) 60 parts, light calcium carbonate (TP121Z Okutama Industries) 30 parts pigment, 0.2 parts polyacrylic acid soda as a dispersant. Then, the pigment slurry dispersed with a serie mixer was added to prepare a pigment slurry having a solid content concentration of 60%.

[0033] Defoaming simultaneous 1J (San Nopco 1407 / San Nopco) 0.5 part, release agent (Nopcoat C104Z made by San Nopco) 5 parts, Styrene butadiene copolymer latex A (Glass transition temperature _ 10 as adhesive) C., particle size 190 nm) 15 parts, casein 7 parts (latex rate: 68%), and water were added to prepare a coating solution with a solid content of 50%. One side was coated with a blade coater on a white paperboard having a basis weight of 430 g / m ² so that the coating amount was 29 g / m ² and dried. The coated paper obtained in this way is rewet on the surface of the coating layer with a rewetting liquid (polyethylene emulsion 0.5% concentration), and then applied to a press dip formed by a foamer roll and a cast drum. Pass through the paper, press on a cast drum with a speed of 100m / min, and a surface temperature of 115 ° C, dry, and then release from the cast drum with a strip-off roll, and a basis weight of 460g / m ² A cast coated paper was obtained. This cast coated paper was used as a ton base paper for thin paper.

[0034] Carton base paper for thin paper was printed so that letters and designs would appear on the faces A, B, C, D, and E in Fig. 1 when a thin paper box was formed in the printing process (offset printing). The printed area was 20% of the total area of A + B + C + D + E. After that, a punching machine was used to punch out the box, and it was processed so that the perforation for removing the sewing machine and the line for folding the box came to the part E on the top of Fig. 1 to obtain a thin paper carton. .

[0035] Further, after pasting a film on the back side of the E side in top view 1 with a window pasting machine, punching out with a sack machine, and then applying a vinyl acetate adhesive to the paste margin in the developed box. Folded and crimped.

Next, in the tissue processing and manufacturing process (cartner) shown in FIG. 2, 200 sets of facial tissue were packed to obtain a box containing tissue. [Example 10]

In Example 9, the cast paint was applied with a reverse roll coater attached to the cast coater so that the coating amount was 30 g / m ² per side, and then coagulated with a calcium formate aqueous solution (10%). The wet coating layer is gelled by contact with the liquid, and the gelled coating layer is passed through a press ep formed by a foamer roll and a cast drum, and the speed is 70 m / min and the surface temperature is 115 ° C. A box with tissue is obtained in the same way as in Example 9, except that the cast coated paper by the coagulation method is made into a carton base paper for thin paper by releasing from the cast drum with a strip-off roll after pressing and drying to the cast drum. It was.

[Example 11]

In Example 9, instead of the white paperboard having a basis weight of 430 gZm ^2, a white paperboard having a basis weight of 330 g / m ² was used to obtain a base paper carton base paper for cast paper having a basis weight of 360 g / m ² . Next, offset printing was performed so that the printing area (A, B, C, D, E) was 40%. After the printing process in the manufacturing process of the thin paper carton described in Example 9, the same process was followed and the toilet paper was packed in the thin paper box processing process to obtain a box with toilet paper.

[Example 12]

In Example 9, fine titanium oxide slurry A (CSB-M; Sakai Chemical Co., Ltd .; secondary particle diameter 20-30 nm, secondary particle average particle diameter lOOOnm) 10 parts (solid content), colloidal silica (Nissan Chemical Co., Ltd.) SNOWTEX 40) Instead of 16 parts, fine titanium oxide slurry A (CSB-M manufactured by Sakai Chemical Co., Ltd .; secondary particle diameter 20-30 nm, secondary particle average particle diameter lOOOnm) 10 parts (solid content), colloidal silica (Snowtex 40, manufactured by Nissan Chemical Co., Ltd.) A box containing tissue was obtained in the same manner as in Example 9 except that the amount was changed to 10 parts.

[Comparative Example 4]

In Example 9, instead of 10 parts of titanium oxide slurry, 16 parts of colloidal silica, 60 parts of kaolin (product name: UW-90Z Engelhard), 30 parts of light calcium carbonate (TP121Z, manufactured by Okutama Kogyo) , Kaolin (trade name: UW-90 / manufactured by Engelhard) 70 parts, light calcium carbonate (TP121Z Okutama Kogyo Co., Ltd.) 30 parts were obtained, except that cast coated paper was obtained in the same manner as in Example 9. . Use this cast coated paper as a carton for thin paper Paper was used and a box containing tissue was obtained in the same manner as in Example 9.

[0038] Table 2 shows the results.

(Evaluation method 2)

(8) Fading test: Before UV irradiation and UV irradiation (illuminate UV light with ^2.5 mW / cm ² intensity with black light) Measure and evaluate the decrease rate of ISO whiteness after 24 hours did.

[0039] Decrease rate of whiteness (%) = (whiteness before UV irradiation minus whiteness after UV irradiation) / whiteness before UV irradiation X 100

(9) Suitability of carton scratches: When making a box from a carton base paper, the difficulty of scratching the coating layer surface was visually evaluated in the following four stages.

◎: Very good, ○: Slightly better, △: Slightly inferior X: Very inferior

(10) Running performance with a ton of force: The running performance when producing a ton of paper for thin paper and when processing a thin paper box was compared in the following four stages.

◎: Very good, ○: Somewhat excellent, △: Somewhat inferior, X: Inferior

[0040] [Table 2]

From Table 2, it can be seen that Examples 9 to 12 have high white paper gloss, excellent photocatalytic effect, fading property, ability to scratch a ton, and carton-carrying ability such as carton running ability. It is. On the other hand, Comparative Example 4 is inferior in the photocatalytic effect, fading property, and carton scratchability.

Claims

The scope of the claims

[1] A cast coated paper that is provided with a cast coating layer mainly composed of a pigment and an adhesive on the base paper, and presses the wet cast coating layer against the heated mirror drum surface and then dries to finish. In other words, cast coated paper containing titanium oxide having an average secondary particle diameter of 300 nm to 2000 nm per 100 parts by weight of pigment in the cast coated layer:! To 30 parts by weight.

[2] The cast coating layer contains 5 to 40 parts by weight of an organic adhesive with respect to 100 parts by weight of the pigment, and 50% by weight or more of the organic adhesive is a copolymer latex. Cast coated paper as described in 1.

[3] The cast coated paper according to claim 1 or 2, wherein a copolymer latex having a glass transition temperature of -20 to 40 ° C is used as an adhesive in the cast coated layer. .

[4] A cast coated paper that is provided with a cast coating layer mainly composed of a pigment and an adhesive on the base paper, and presses and dries the wet cast coating layer on the heated mirror drum surface. In addition, the cast coating layer contains titanium oxide having an average secondary particle size of 300 nm to 2000 nm per 100 parts by weight of pigment:! To 30 parts by weight, and the titanium oxide is mixed with silica sol or alumina zonole. Cast coated paper that is made.

[5] In the mixing treatment, the mixing ratio of titanium oxide: silica sol or alumina sol is 2 ::! To 1

5. The cast coated paper according to claim 4, wherein

[6] The cast coated paper according to any one of claims 1 to 5, wherein the glossiness of the blank paper on the cast surface conforming to JIS—P8142 is 80% or more.

[7] The cast coated paper according to any one of [1] to [6], wherein a primary particle size of the titanium oxide is 5 to:! OOnm.

[8] The cast coated paper according to any one of [1] to [7], wherein the wet coated layer is once dried and cast-finished by a rewetting method in which the coated layer is rewet with a rewetting liquid.

[9] A thin paper carton or a thin paper box produced using the cast coated paper according to any one of claims 1 to 8.