JP2010270418A - Coating agent for preventing strike through, coating composition containing the same, and paper and newsprint paper applied with the coating composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating agent for preventing strike through, having a high oil absorptivity value and showing less strike through on printing, a coating composition, paper and newsprint paper. <P>SOLUTION: This coating agent for preventing the strike through is obtained by modifying [A] an amide-based compound (i) having 100 to 250 mgKOH/g and (ii) obtained by reacting (a) a polyalkylene amine with (b) 5 to 45 mol% dibasic carboxylic acids based on the primary amino groups contained in the polyalkylene amine (a), and (c) 25 to 75 mol% 12-24C fatty acids based on the total number of moles of primary amino groups and secondary amino groups contained in the polyalkylene amine (a), with 50 to 100 mol% epihalohydrin (f) based on the active hydrogens of residual amino groups of the amide-based compound [A] in an aqueous solution containing (d) a water soluble organic acid and (e) a nonionic emulsifier and/or cationic emulsifier. The coating composition containing the striking through-preventing agent, and paper and newsprint paper applied with the coating composition are also provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a back-through prevention coating agent, a coating composition containing the coating agent, paper coated with the coating composition, and newspaper printing paper.

  In recent years, newspaper printing paper has been required to be lighter and to have higher deinked pulp content, and has shifted from acidic papermaking to neutral papermaking. Also in printing, offsetting, printing speed, and colorization are rapidly progressing, and the demand for printability is becoming stricter.

  Accordingly, newspaper printing paper has a tensile strength that can withstand high-speed offset printing, a surface strength that does not generate blanket paper dusting during printing, a low drip resistance that prevents paper from being removed from the blanket during printing, and a dampening during printing. There are demands for surface sizing properties with respect to water, prevention of ink back-through, and good ink deposition.

  For this reason, neutral newsprint and its manufacturing method are proposed (for example, refer to patent documents 1). However, it has not been able to provide newspaper printing paper that is highly suitable for high-speed printing and has excellent printing quality.

  In addition, it is publicly known (for example, refer to Patent Documents 2 and 3) that an amide compound obtained by reaction of a polyalkylene polyamine and a fatty acid and a reaction product of epihalohydrin are effective as main components of a paper sizing agent. . Further, it is known as an opacity improver and a porosity improver (for example, see Patent Documents 4 and 5) for uses other than the sizing agent, and is useful for improving the peelability from a paper drum dryer (for example, Patent Document 6) is also known, but these patent documents do not describe prevention of see-through dry ink penetration.

Japanese Patent No. 2889159 Japanese Patent Publication No.42-2922 JP 47-11306 A JP 61-252400 A JP 2000-273792 A JP 59-30997

  An object of the present invention is to provide a coating agent for preventing show-through, which has a high oil absorption value and has less show-through during printing. Moreover, this invention makes it a subject to provide the coating composition containing this coating agent for back-through prevention, the paper and newspaper printing paper which apply | coated this coating composition.

  As a result of diligent research to solve the above-mentioned problems, the present inventors can obtain a specific amide compound by modifying with a specific proportion of epihalohydrin in an aqueous solution containing a specific organic acid and a specific emulsifier. The present inventors have found that the above problems can be solved by using a back-through prevention coating agent, and have completed the present invention.

That is, the present invention
(1) (i) The amine value is 100 to 250 mg KOH / g, and (ii) 5 moles per mole of primary amino groups contained in polyalkylene polyamine (a) and polyalkylene polyamine (a). Carbon number of 25-75 mol% with respect to the total mol number of primary amino group and secondary amino group contained in -45 mol% of dibasic carboxylic acid (b) and said polyalkylene polyamine (a) An amide compound [A] obtained by reacting with 12 to 24 fatty acids (c),
In an aqueous solution containing the water-soluble organic acid (d) and the nonionic emulsifier and / or the cationic emulsifier (e), 50 to 100 mol% with respect to the active hydrogen of the residual amino group of the amide compound [A] A coating agent for preventing breakthrough obtained by modifying with epihalohydrin (f)
(2) The amount of the water-soluble organic acid (d) is 1 to 100 mol% based on the active hydrogen of the remaining amino group of the amide compound [A], and the nonionic emulsifier and / or the cationic emulsifier. The amount of (e) is 1 to 20% by mass with respect to the amide-based compound [A],
(3) The back-through prevention coating agent according to (1) or (2), wherein the fatty acid (c) is a saturated fatty acid,
(4) A coating composition formed from the back-through prevention coating agent according to any one of (1) to (3) above and at least one modified starch,
(5) Paper characterized by being obtained by applying the coating composition according to (4) to the surface of a base paper,
(6) Newsprint printing paper obtained by applying the coating composition according to (4) above to a base paper surface,
(7) The base paper of (6) has a basis weight of 50 g / m ² or less, an opacity of 90% or more, a paper surface pH of 5 to 9, an ash content of 5 to 40% by mass, and a calcium carbonate content. The newspaper printing paper according to the above (6), wherein is 5 to 40% by weight of neutral paper,
(8) The newspaper printing paper according to the above (6) or (7), which is offset-printed by using a penetrating dry type ink on a rotary printing press.

  It is possible to provide a coating agent for preventing through-through, a coating composition, paper, and newspaper printing paper that have excellent oil absorption and little through-through during printing.

(I) The amine value is 100 to 250 mg KOH / g, and (ii) 5 to 45 moles relative to the number of moles of the primary amino group contained in the polyalkylene polyamine (a) and the polyalkylene polyamine (a). % Of the dibasic carboxylic acid (b) and the total number of moles of the primary amino group and the secondary amino group contained in the polyalkylene polyamine (a) is 25 to 75 mol% of 12 to 24 carbon atoms. An amide compound [A] obtained by reacting a fatty acid (c) of
In an aqueous solution containing the water-soluble organic acid (d) and the nonionic emulsifier and / or the cationic emulsifier (e), 50 to 100 mol% with respect to the active hydrogen of the residual amino group of the amide compound [A] It is a coating agent for preventing breakthrough obtained by modification with epihalohydrin (f).

  The amide compound [A] is a dibasic carboxylic acid (b) of 5 to 45 mol% with respect to the number of moles of primary amino group contained in the polyalkylene polyamine (a) and the polyalkylene polyamine (a). And 25-75 mol% C12-24 fatty acid (c) is made to react with respect to the total number of moles of the primary amino group and secondary amino group contained in the polyalkylene polyamine (a). Can be obtained.

  Examples of the polyalkylene polyamine (a) used in the present invention include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, dipropylenetriamine, tripropylenetetramine, hexamethylenediamine, and imino. Bispropylamine and alkylene oxide adducts of these amines are mentioned. These can form an amide-type compound by reacting with a dibasic carboxylic acid (b) and a C12-24 fatty acid (c). Among these, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine are preferable, and tetraethylenepentamine is particularly preferable. These may be used alone or in combination of two or more.

  The dibasic carboxylic acid (b) used in the present invention is a dibasic carboxylic acid having two carboxyl groups in the molecule and / or a derivative thereof, which reacts with polyalkylene polyamines to form an amide. It suffices if a compound can be formed. Examples of the derivatives include monoesters, diesters, and acid anhydrides of these dibasic carboxylic acids. Examples of the dibasic carboxylic acid include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, brassic acid, dodecanedioic acid, terephthalic acid, and the like. Is preferably a dibasic carboxylic acid having 5 to 10 carbon atoms. Moreover, as monoester and diester of dibasic carboxylic acid, Preferably it is C1-C5, Most preferably, C1-C3 lower alcohol (methyl, ethyl, propyl) ester can be mentioned. Examples of the acid anhydride include an intramolecular dehydration condensate of a free acid, and a condensate of a lower carboxylic acid, preferably a lower carboxylic acid having 1 to 5 carbon atoms. Particularly preferred industrially preferred dibasic carboxylic acids include adipic acid, glutaric acid dimethyl ester, and adipic acid dimethyl ester. The above dibasic carboxylic acids can be used alone or in combination of two or more.

  The dibasic carboxylic acid (b) needs to be used in an amount of 5 to 45 mol% based on the number of moles of the primary amino group contained in the polyalkylene polyamine (a). When less than 5 mol% of the dibasic carboxylic acid (b) is reacted with respect to the number of moles of the primary amino group contained in the polyalkylene polyamine (a), the amide compound [A] at the time of melting Since the viscosity is low and the number of cationic sites in one unit is small and it is difficult to fix to cellulose, the anti-back-through coating agent can easily penetrate into the paper, resulting in low oil absorption and low back-through prevention. The effect is inferior, and when the dibasic carboxylic acid (b) is reacted in excess of 45 mol%, the amide compound [A] is gelled during production, or the viscosity at the time of melting is increased on paper. The spread of the oil is poor and the alignment takes time, so the value of the oil absorption becomes low, and the effect of preventing the breakthrough is poor.

  The fatty acid (c) having 12 to 24 carbon atoms used in the present invention may be saturated or unsaturated, and specifically includes dodecanoic acid (lauric acid) or carbon having 12 carbon atoms. Tetradecanoic acid (myristic acid) having 14 carbon atoms, pentadecanoic acid (pentadecylic acid) having 15 carbon atoms, hexadecanoic acid (palmitic acid) having 16 carbon atoms, 9-hexadecenoic acid (palmitoyl acid), heptadecanoic acid having 17 carbon atoms (margaric acid) ), C18 octadecanoic acid (stearic acid), cis-9-octadecenoic acid (oleic acid), 11-octadecenoic acid (vaccenic acid), cis, cis-9,12-octadecadienoic acid (linoleic acid), 9,12,15-octadecanetrienoic acid ((9,12,15) -linolenic acid), 6,9,12-octadecatrienoic acid ((6,9,1 ) -Linolenic acid), 9,11,13-octadecatrienoic acid (eleostearic acid), 19-carbon nonadecanoic acid (tuberculostearic acid), 20-carbon icosanoic acid (arachidic acid), 8,11 -Icosadienoic acid, 5,8,11-icosatrienoic acid, 5,8,11-icosatetraenoic acid (arachidonic acid), carbon number 22 docosanoic acid (behenic acid), carbon number 24 tetradocosanoic acid (lignoceric acid), cis- Examples thereof include 15-tetradocosanoic acid (nervonic acid), and even these esters can be used. Among these, saturated fatty acids are preferable, and those having 18 to 24 carbon atoms are preferable. Said fatty acid (c) can be used 1 type or in combination of 2 or more types.

  The fatty acids (c) having 12 to 24 carbon atoms must be used in an amount of 25 to 75 mol% based on the total number of moles of primary amino groups and secondary amino groups contained in the polyalkylene polyamine (a). . When fatty acids (c) having 12 to 24 carbon atoms of less than 25 mol% are used with respect to the total number of primary amino groups and secondary amino groups contained in the polyalkylene polyamine (a), they are derived from fatty acids. Since the number of alkyl groups decreases, the oil absorption value is low, and the effect of preventing the breakthrough is poor. When the fatty acid (c) having more than 75 mol% and having 12 to 24 carbon atoms is used, the hydrophilicity is lowered and the breakthrough is caused. Since the dispersibility of the coating agent for prevention is lowered, the value of oil absorption is low, and the effect of preventing back-through is inferior.

  The amine value of the amide compound [A] needs to be 100 to 250 mgKOH / g. If the amine value is less than 100, the number of cationic sites that can be fixed on cellulose is reduced, and the number of components that work effectively is reduced. Therefore, the oil absorption value is low, and the effect of preventing ink back-through is inferior. Therefore, although fixing to cellulose is excellent, the hydrophobicity is inferior, so the value of oil absorption is low, and the effect of preventing ink from falling through is inferior.

The amine value of the amide compound [A] in the present invention is determined by measuring and calculating as follows. Further, the amine value of the amide compound [A] indicates a residual amino group.
Amine value = residual amino group = (V × F × 0.5 × 56.1) / S
However, V: 1/2 titration of normal hydrochloric acid in methanol (cc)
F: 1/2 titer of normal hydrochloric acid methanol solution S: solid content of collected sample (g)

  The reaction of the polyalkylene polyamine (a) with the fatty acids (c) and the dibasic carboxylic acids (b) is carried out by heating to 100 to 200 ° C. The reaction time is usually 0.5 to 10 hours, and preferably 2 to 6 hours. There is no limitation on the method of mixing the polyalkylene polyamine (a) with the fatty acids (c) and the dibasic carboxylic acids (b) during the reaction, and usually the polyalkylene polyamine (a) is mixed with the dibasic carboxylic acids (b). A method in which the reaction is proceeded by mixing the fatty acid (c) with the fatty acid (c), and the reaction is proceeded by mixing the fatty acid (c) with the reaction product of the dibasic carboxylic acid (b) and the polyalkylene polyamine (a). The method is preferred. A catalyst for the amidation reaction is not particularly required. However, as the catalyst for the amidation reaction, sulfonic acids such as sulfuric acid, benzenesulfonic acid and paratoluenesulfonic acid, or a catalyst usually used for the amidation reaction are used. May be. The amount used is usually 0.005 to 0.1 mol, preferably 0.01 to 0.05 mol, per 1 mol of polyalkylene polyamine (a).

The coating agent for preventing strikethrough according to the present invention comprises an amide compound [A] in an aqueous solution containing a water-soluble organic acid (d) and a nonionic emulsifier and / or a cationic emulsifier (e). It is obtained by modifying with 50 to 100 mol% of epihalohydrin (f) with respect to the active hydrogen of the remaining amino group of A].
Examples of the water-soluble organic acid (d) used in the present invention include water-soluble organic acids having a carboxylic acid such as formic acid, acetic acid and propionic acid.

  The water-soluble organic acid (d) is preferably from 1 to 100 mol%, more preferably from 50 to 90 mol%, based on the active hydrogen of the remaining amino group of the amide compound [A], thereby enhancing dispersibility. Therefore, it is preferable.

  Of the nonionic emulsifier and / or cationic emulsifier (e) used in the present invention, examples of the nonionic emulsifier include fatty acid sorbitan esters and fatty acids having 4 to 20 carbon atoms in the alkyl group and / or alkenyl group. Examples include polyglycol esters, fatty acid amides, and various polyalkylene oxide type nonionic surfactants. Polyalkylene oxide type nonionic surfactants include fatty acid alkylene oxide sorbitan esters, polyoxyalkylene fatty acid esters, polyoxyalkylene fatty acid amides, polyoxyalkylene fatty alcohols, polyoxyalkylene aliphatic amines, polyoxyalkylene aliphatic mercaptans. , Polyoxyalkylene alkyl ether, polyoxyalkylene alkyl aryl ether and the like. Among these, it is preferable that it is an alkylene oxide adduct excellent in emulsification dispersibility, and it is preferable that 1-20 mol is added as an alkylene oxide per molecule of the emulsifier. It is particularly preferable that the alkyl group of the alkylene oxide has 2 to 4 carbon atoms.

  Of the nonionic emulsifier and / or the cationic emulsifier (e) used in the present invention, examples of the cationic emulsifier include a long-chain alkylamine salt having 4 to 20 carbon atoms in the alkyl group and / or alkenyl group. , Polyoxyalkyleneamines, tetraalkyl quaternary ammonium salts, trialkylbenzyl quaternary ammonium salts, alkyl imidazolium salts, alkyl pyridinium salts, alkyl quinolinium salts, alkyl phosphonium salts, alkyl sulfonium salts, etc., and amphoteric surface activity Examples of the agent include various betaine surfactants. Among these, it is preferable that it is an alkylene oxide adduct excellent in emulsification dispersibility, and it is preferable that 1-20 mol is added as an alkylene oxide per molecule of the emulsifier. It is particularly preferable that the alkyl group of the alkylene oxide has 2 to 4 carbon atoms.

  The nonionic emulsifier and / or the cationic emulsifier (e) is 1 to 20% by mass with respect to the solid content of the amide compound [A] in order to increase dispersibility while suppressing foaming. preferable.

Examples of the epihalohydrin (f) used in the present invention include epichlorohydrin, epibromohydrin, etc. Among them, epichlorohydrin is preferable.
The usage-amount of epihalohydrin (f) needs to be 50-100 mol% with respect to the active hydrogen of a residual amino group.

If the amount of the epihalohydrin (f) used is less than 50 mol% with respect to the active hydrogen of the residual amino group of the amide compound [A], the cationic property of the back-through prevention coating agent is lowered, and it is fixed to cellulose. Since it becomes difficult, the value of oil absorption is low and the effect of preventing back-through is inferior, and when it exceeds 100 mol%, only unreacted substances increase.
The reaction of the amide compound [A] and the epihalohydrin (f) in an aqueous solution containing the water-soluble organic acid (d) and the nonionic emulsifier and / or the cationic emulsifier (e) is heated to 40 to 95 ° C. Is done. The reaction time is usually 1 to 8 hours, with 3 to 6 hours being preferred.

  The pulp used for the base paper to which the coating agent for preventing breakthrough of the present invention is applied is bleached kraft pulp or sulfite pulp, or unbleached chemical pulp, groundwood pulp, mechanical pulp, thermomechanical pulp, etc. Examples include bleached or unbleached high-yield pulp, or used paper pulp such as used newspaper, magazine used paper, cardboard used paper, or deinked used paper. From the viewpoint of resource saving and recycling, the amount of waste paper pulp is preferably 50% by mass or more, more preferably 70% by mass or more, based on the total pulp solid content.

  To obtain paper, sizing agents such as fillers, dyes, rosin sizing agents for acidic paper making, alkyl ketene dimer or alkenyl succinic anhydride sizing agents for neutral paper making, and rosin sizing agents for neutral paper making In addition, other additives such as dry paper strength enhancer, wet paper strength enhancer, yield improver, drainage improver, and antifoaming agent are also used as necessary to express the physical properties required for each paper type. May be used. Examples of the filler include clay, talc, white carbon, titanium oxide, and heavy or light calcium carbonate. These may be used alone or in combination of two or more.

The base paper thus obtained has a basis weight of 50 g / m ² or less, an opacity of 90% or more, a paper surface pH of 5 to 9, and an ash content of 5 to 40% by mass relative to the absolute dry mass of the paper. The content of calcium carbonate is preferably neutral newsprint with 5 to 40% by mass relative to the absolute dry mass of the paper. The opacity can be measured according to ISO 2471. Ash content can be measured according to ISO 1762. When measuring the content of calcium carbonate, the ignition temperature is 575 ° C., and when measuring the content of fillers other than calcium carbonate, the ignition temperature is 900 ° C.

  Examples of the coating machine for applying the back-through prevention coating agent of the present invention include a size press, a film press, a gate roll coater, a shim sizer, a blade coater, a calendar, a bar coater, a knife coater, and an air knife coater. , And curtain coaters can be used. In addition, a coating agent for preventing penetration from the base paper surface can be applied by a spray coating machine.

  When applying the coating agent for preventing strike-through of the present invention, starches such as oxidized starch, phosphate esterified starch, enzyme-modified starch, cationized starch, celluloses such as carboxymethylcellulose, polyvinyl alcohol, polyacrylamide And water-soluble polymers such as sodium alginate can also be used as the coating liquid. Moreover, you may use together additives, such as a surface sizing agent, an antiskid agent, antiseptic | preservative, a rust preventive agent, an antifoamer, a viscosity modifier, dye, and a pigment. Among these, in particular, for coating containing at least one modified starch selected from modified starches such as oxidized starch, phosphate esterified starch, enzyme-modified starch, and cationized starch, and a coating agent for preventing back-through. A composition is preferred.

  Examples of paper that can be obtained by coating the base paper with the back-through prevention coating agent of the present invention include various papers and paperboards. For example, recording paper such as PPC paper, ink jet recording paper, pressure-sensitive paper, photographic printing paper, laser printer paper, foam paper, thermal transfer paper, and thermal recording paper, art paper, cast coated paper, high quality coated paper, and medium quality coated paper Coated paper such as paper, kraft paper, wrapping paper such as pure white roll paper, other base paper such as notebook paper, book paper, printing paper and newspaper printing paper, processing base paper such as processing base paper such as photographic paper, manila ball, Examples include paperboard paperboard such as white balls and chip balls, and paperboard such as liners. Among these, as the paper that can be applied with the back-through prevention coating agent of the present invention and can better exhibit the back-through prevention effect, newspaper printing paper is preferable, and neutral newspaper printing paper is more preferable. . In particular, newspaper printing paper that is offset-printed using a penetrating dry type ink on a rotary printing press in which show-through is a problem is preferable.

  The concentration of the back-through prevention coating agent in the coating solution used when applying the back-through prevention coating agent of the present invention is usually 0.01 to 3% by mass, preferably 0.05 to 2% by mass. If it is less than 0.01% by mass, the effect of preventing the breakthrough may be insufficient. Even if it exceeds 3% by weight, the effect of preventing the breakthrough is low, which is economically disadvantageous.

Also, usually, the coating weight is, 0.01 to 0.3 g / ^{m 2} by solid content of the anti-coating agents strike through, preferably 0.01 to 0.1 g / ^{m 2.} If it is within the above range, the effect of preventing the breakthrough is exhibited particularly well.

  Examples of the present invention are shown below, but the technical scope of the present invention is not limited to these embodiments. In the following, “parts” and “%” mean “parts by mass” and “% by mass”, respectively.

Production Example 1 of Polymer Emulsifier
170 parts of styrene, 57 parts of dimethylaminoethyl methacrylate, 3.6 parts of azobisisobutyronitrile and 68 parts of isopropyl alcohol were added to a 1 liter four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen inlet tube. Charged and held at 80 ° C. for 3 hours, then 0.2 part of asobisisobutyronitrile was charged and further held at the same temperature for 2 hours. Subsequently, 22.3 parts of 90% acetic acid (100 mol% with respect to dimethylaminoethyl methacrylate) and 558 parts of water were added, and isopropyl alcohol was distilled off. Thereafter, 13 parts of water and 31 parts of epichlorohydrin as a quaternizing agent (100 mol% with respect to dimethylaminoethyl methacrylate) were charged and held for 2 hours. Then, it diluted with water so that it might become solid content 25%, and obtained cationic copolymer aqueous solution. This is used as a polymer emulsifier.

Example 1
A 1 liter four-necked round bottom flask equipped with a thermometer, a cooler, a stirrer, and a nitrogen inlet tube is charged with 1 mol of tetraethylenepentamine and 0.5 mol of adipic acid and heated to 170 ° C. to produce After reacting for 2 hours while removing water, 1.6 mol of stearic acid was further added and reacted at 170 ° C. for another 5 hours. 50.0 g of this amide compound, 2.5 g of isopropyl alcohol, 369.1 g of water, 5.0 g of nonionic emulsifier (Newcol 2320 (manufactured by Nippon Emulsifier Co., Ltd.)), 5.8 g of acetic acid, thermometer, reflux condenser, stirring The mixture was charged into a 500 ml four-necked flask equipped with a machine and a dropping funnel, heated to 50 ° C., and stirred for 1 hour. After adding 11.2 g of epichlorohydrin (70 mol% with respect to the active hydrogen of the remaining amino group), the mixture was reacted at 50 ° C. for 3 hours and further at 80 ° C. for 3 hours, then cooled to the back of 15% solid content A coating agent A for preventing slippage was obtained. Table 2 shows the properties of the obtained anti-back-through coating agent A.

Examples 2 to 25, Comparative Examples 2 to 7
Except for changing as shown in Table 1, coating agents B to Y and a to f for preventing back-through were obtained in the same manner as in Example 1. Table 2 shows properties of the obtained anti-back-through coating agents B to Y and a to f. In Comparative Example 1, hydroxyethylated starch was used in place of the coating agent for preventing breakthrough.

Explanation of abbreviations in Table 1 TEPA: Tetraethylenepentamine TETA: Triethylenetetramine DETA: Diethylenetriamineamito 320: Polyoxyethylene alkylamine (manufactured by Kao Corporation) (Type: p-EO-C18 amine)
Polymer: Polymer emulsifier obtained in Production Example 1 of polymer emulsifier N2308: New Coal 2308 (manufactured by Nippon Emulsifier Co., Ltd.) (Type: p-EO-C12-13 ether: polyoxyethylene alkyl ether)
N2360: New Coal 2360 (Nippon Emulsifier Co., Ltd.) (Type: p-EO-C12-13 ether: Polyoxyethylene alkyl ether)
N2320: New Coal 2320 (Nippon Emulsifier Co., Ltd.) (Type: p-EO-C12-13 ether: Polyoxyethylene alkyl ether)
EpiCl: Epichlorohydrin

Manufacture of base paper for neutral newspaper printing paper Canadian Standard Freeness (CSF) 160ml, 2.5% deinked pulp slurry, 9% (based on absolute mass) calcium carbonate (Okutama Kogyo Co., Ltd.) TP121S) and 0.25% (absolutely dry basis) sulfuric acid band to pulp were sequentially added, and the pulp slurry was diluted to a concentration of 0.25% with pH 7.5 dilution water. Paper was made with a test paper machine so that the basis weight was 48 g / m ² . The papermaking pH at this time was 7.5. The wet paper was dried using a drum dryer at 100 ° C. for 80 seconds to obtain a base paper for neutral newspaper printing paper. The opacity of the obtained base paper is 92%, the paper surface pH is 7, the ash content is 10% by mass with respect to the absolute dry mass of the paper, and the calcium carbonate content is 7% by mass with respect to the absolute dry mass of the paper. Met.

Preparation of coated paper Hydroxyethylated starch was diluted with water to a concentration of 12%, gelatinized at 95 ° C., and a coating agent for preventing see-through was added to the obtained hydroxyethylated starch solution. The composition of the obtained coating composition was adjusted so as to be 10% of hydroxyethylated starch and 0.5% of a coating agent for preventing back-through. This coating composition was applied to the base paper of the above-mentioned neutral newspaper printing paper. Coating was performed with a 3-bar coater to obtain neutral newspaper printing paper. The coating amount of the back-through prevention coating agent was 0.08 g / m ² in terms of solid content. The obtained neutral newspaper printing paper was used as a test paper and conditioned for 24 hours in a constant temperature and humidity (23 ° C., 50% relative humidity) environment. Evaluation was performed as follows.

(Evaluation methods)
Oil absorption: JAPAN TAPPI No. In accordance with No. 33, a mixed oil of soybean oil / petroleum solvent (manufactured by Nippon Oil Co., Ltd .; AF Solvent 6) = 1/1 (mass% / mass%) is dropped onto the paper surface, and the oil droplets are absorbed by the paper. The time until it disappears from the paper surface was measured. The drop amount of the mixed oil was 1 μl. The higher the number, the less oil will penetrate into the paper.

Back-through value: One-sided printing was performed on a paper sample by using a RI printer and keyless offset newspaper ink. The sample was left in an atmosphere of 20 ° C. and 65 RH%, and after 1 hour and 24 hours from the stand, the reflectance of the printed back surface was measured with a Macbeth reflection densitometer, and the show-through value was calculated by the following equation.
Strike through value (%) = (reflectance of printed back surface / reflectance of unprinted back surface) × 100
Table 3 shows the evaluation results for Examples 1 to 25 and Comparative Examples 1 to 7.

  From the results of Table 3, the oil absorption value and the strikethrough value are increased by applying the coating composition containing the strikethrough prevention coating agent of the present invention to the paper surface. That is, it can be seen that the formation of a film that suppresses ink permeation on the paper surface suppresses ink permeation into the paper.

Claims (8)

(I) The amine value is 100 to 250 mg KOH / g, and (ii) 5 to 45 moles relative to the number of moles of the primary amino group contained in the polyalkylene polyamine (a) and the polyalkylene polyamine (a). % Of the dibasic carboxylic acid (b) and the total number of moles of the primary amino group and the secondary amino group contained in the polyalkylene polyamine (a) is 25 to 75 mol% of 12 to 24 carbon atoms. An amide compound [A] obtained by reacting a fatty acid (c) of
In an aqueous solution containing the water-soluble organic acid (d) and the nonionic emulsifier and / or the cationic emulsifier (e), 50 to 100 mol% with respect to the active hydrogen of the residual amino group of the amide compound [A] A coating agent for preventing breakthrough obtained by modification with epihalohydrin (f).   The amount of the water-soluble organic acid (d) is 1 to 100 mol% based on the active hydrogen of the remaining amino group of the amide compound [A], and the nonionic emulsifier and / or the cationic emulsifier (e). The amount of is 1-20 mass% with respect to amide type compound [A], The coating agent for back-through prevention of Claim 1 characterized by the above-mentioned.   The back-through prevention coating agent according to claim 1, wherein the fatty acids (c) are saturated fatty acids.   The coating composition formed with the coating agent for back-through prevention of any one of Claims 1-3, and at least 1 type of modified starch.   Paper obtained by applying the coating composition according to claim 4 to the surface of a base paper.   Newsprint printing paper obtained by applying the coating composition according to claim 4 to the surface of a base paper. The base paper according to claim 6 has a basis weight of 50 g / m ² or less, an opacity of 90% or more, a paper surface pH of 5 to 9, an ash content of 5 to 40% by mass, and a calcium carbonate content of 5 Newspaper printing paper, characterized in that it is neutral paper of up to 40% by weight.   The newspaper printing paper according to claim 6 or 7, wherein offset printing is performed using a penetrating dry ink on a rotary printing press.