JP4941010B2 - Undercoat coating liquid for water repellent, water repellent paper and method for producing the same - Google Patents

Description

  The present invention relates to a water-repellent undercoat coating solution applied to paper prior to the application of a water-repellent agent, water-repellent paper, and a method for producing water-repellent paper.

  For exterior liners (hereinafter sometimes abbreviated as liners) used for frozen food corrugated cardboard, vegetable corrugated cardboard, etc., paperboard made from kraft pulp or kraft pulp wastepaper is used as a repellent made of wax emulsion. A solution coated with a liquid has been used in the past. However, in recent years, from the viewpoint of protecting wood resources, there is a tendency for the ratio of used paper to increase as a paperboard raw material.

  The surface properties of paperboard change as the mixing ratio of used paper with a high filler and fine fiber content increases, and even if a water repellent is applied to paperboard with a high ratio of used paper, that alone is sufficient for water repellency. The effect is no longer obtained. By the way, in the production of corrugated cardboard, when the core base paper is bonded to a paperboard (liner) coated with a water repellent, the water repellent melts due to the heat of the corrugator, and this penetrates into the gaps between the pulp fibers. The phenomenon that the water repellency decreases is generally referred to as “water repellent sinking.” Paperboard with a large amount of used paper tends to sink water repellent, and if this occurs, a sufficient water repellent effect can be obtained. Usually there is no. This sinking of the water repellent could not be suppressed even when the amount of anionic internal additive sizing agent, anionic paper strength agent, and polyvinyl alcohol, which are currently widely used, is increased.

Therefore, in order to solve these problems, a quaternary cationic copolymer synthesized using a styrene monomer and a vinyl monomer having a tertiary amino group as an essential monomer component, and a polyamide polyamine-epihalohydrin resin are included. A method for producing water-repellent paper having a two-layer structure of an undercoat layer and a water-repellent layer has been proposed (see Patent Document 1). However, when a cationic copolymer is used, the surface strength is improved because the compatibility between the polyvinyl alcohol and starch used to increase the surface strength of water repellent paper and the cationic copolymer is not good. There was a problem that the means to make it limited.

The present applicant obtained by emulsion polymerization of a hydrophobic unsaturated monomer in the presence of a water-soluble copolymer containing a carboxyl group-containing unsaturated monomer and a hydrophobic unsaturated monomer. Has proposed a paper surface sizing agent containing an emulsion (Patent Document 2), but did not disclose any application to a water-repellent paper primer.

JP 2005-336663 A JP-A-8-2468391

In the present invention, the water repellent applied after the water repellent is applied to the base paper on which the water repellent is to be applied, so that the water repellent applied later sinks into the paper layer under the influence of heat. The water-repellent paper and the water-repellent paper having both the coating layer of the primer coating liquid formed on the paper and the water-repellent layer formed thereon are also provided. It aims at providing the manufacturing method of water paper.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a coating liquid containing an emulsion obtained by emulsion polymerization of a predetermined polymerization component. It was.

That is, the present invention provides (meth) acrylic acid and / or (meth) allylsulfonic acid (a), (meth) acrylic acid alkyl esters and / or styrenes (b), and (meth) acrylamide as necessary. And / or a water repellent undercoat coating solution containing an emulsion obtained by emulsion polymerization of a polymerization component comprising N-substituted acrylamides (c) in the presence of an emulsifier and / or a protective colloid ; A water-repellent paper having a coating layer and a water-repellent layer obtained by using an undercoat coating liquid for an agent; a step of coating and drying the base coating liquid for the water-repellent agent on a base paper, and a coating layer provided Further, the present invention relates to a method for producing water-repellent paper having a step of coating and drying a water-repellent agent.

According to the present invention, even when the paper is heated, the water repellent is prevented from sinking, and the water repellency of the resulting water repellent paper can be improved. Moreover, since the undercoat coating liquid for water repellent of the present invention has good compatibility with polyvinyl alcohol, starch and the like, it can be used in combination with these surface strength improvers. Furthermore, the water-repellent paper obtained by the present invention has an effect that the amount of static electricity on the paper surface is reduced, so that paper dust does not easily hit the paper surface during paper cutting.

The undercoating liquid of the present invention comprises (meth) acrylic acid and / or (meth) allylsulfonic acid (a), (meth) acrylic acid alkyl esters and / or styrenes (b), and if necessary ( It is characterized by containing an emulsion obtained by emulsion polymerization of a polymerization component comprising (meth) acrylamide and / or N-substituted acrylamides (c) in the presence of an emulsifier and / or a protective colloid . If not using the emulsion (the use of anionic polymer consisting of polymerizable components as a solution dissolved in a solvent, etc.), water repellency satisfying can not be obtained. The emulsion can be used as such as a primer coating solution.

The polymerization component essentially contains (meth) acrylic acid and / or (meth) allylsulfonic acid (a) (hereinafter referred to as component (a)). These may be alkali metal salts, alkaline earth metal salts and ammonium salts. Along with the polymerization component, crotonic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, cinnamic acid, vinyl ester acid, 2- (meth) acrylamide glycolic Acids, α, β-unsaturated tricarboxylic acids and α, β-unsaturated tetracarboxylic acids and unsaturated carboxylic acid monomers such as alkali metal salts, alkaline earth metal salts and ammonium salts thereof, vinyl sulfonic acid , isoprene sulfonic acid 3-allyloxy-2-hydroxy-propanesulfonic acid, styrenesulfonic acid, and acrylic acid-3-sulfopropyl ester, 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamide-2-methylpropanesulfonic acid, Sulfoethyl acrylate, acrylic acid Sulfates of Dorokishiechiru, alkali metal salts of sulfuric acid esters and their acid acrylic acid polyoxyalkylene oxide and a monomer having a sulfonic acid group such as an alkaline earth metal and ammonium salts, and the like can be used in combination. These may be used alone or in combination of two or more .

The polymerization component essentially contains (meth) acrylic acid alkyl esters and / or styrenes (b) (hereinafter referred to as component (b)). Examples of the (meth) acrylic acid alkyl esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth) isobutyl acrylate, (meth) t-butyl acrylate, (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl 2-ethylhexyl (meth) acrylate, as the styrenes Examples include styrene, α-methylstyrene, vinyltoluene and the like . Along with the polymerization component, aromatic monomers having no ionic functional groups such as benzyl (meth) acrylate, vinyl esters such as vinyl acetate and vinyl propionate, dialkyl diesters of maleic acid and fumaric acid, methyl vinyl ether Etc. can be used together . These may be used alone or in combination of two or more.

The polymerization component may contain (meth) acrylamide and / or N-substituted acrylamides (c) (hereinafter referred to as component (c)) as necessary. Examples of the N-substituted acrylamides include N-alkyl (meth) acrylamide. In addition, together with the polymerization component, (meth) allyl ethers such as (meth) allyl ethyl ether, (meth) allyl esters of saturated carboxylic acids such as (meth) allyl acetate and allyl propionate , (meth) acrylonitrile, Polyfunctional monomers such as (meth) allylformate, methylenebis (meth) acrylamide, 1,3,5-triacryloylhexahydro-S-triazine can be used in combination. In addition , a vinyl monomer having an amino group can be used in combination as long as the effect of the present invention is not affected. Specific examples of the vinyl monomer having an amino group include a vinyl monomer having a secondary amino group such as (meth) allylamine and di (meth) allylamine, dimethylaminoethyl (meth) acrylate, diethylaminoethyl ( (Dialkyl) aminoalkyl (meth) acrylates such as meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylate; dimethylaminohydroxyethyl (meth) acrylate, diethylaminohydroxyethyl (meth) acrylate, dimethylaminohydroxy (Dialkyl) aminohydroxyalkyl (meth) acrylates such as propyl (meth) acrylate and diethylaminohydroxypropyl (meth) acrylate; (Dialkyl) aminoalkyl (meth) acrylamides such as (meth) acrylamide and diethylaminopropyl (meth) acrylamide; vinyl monomers having a tertiary amino group such as vinylpyridine and vinylimidazole, or their hydrochloric acid, sulfuric acid, acetic acid, etc. Salts of inorganic or organic acids, or vinyl monomers containing a quaternary ammonium salt obtained by reaction of the tertiary amino group-containing vinyl monomer with a quaternizing agent such as methyl chloride, benzyl chloride, dimethyl sulfate, epichlorohydrin, etc. - etc. can be mentioned, these vinyl monomers are one or more kinds can be used. Among the vinyl monomers exemplified above, a vinyl monomer having a tertiary amino group or a quaternary amino group is preferable from the viewpoint of cation strength. Specifically, (dialkyl) aminoalkyl (meth) is particularly preferable. Acrylate, (dialkyl) aminoalkyl (meth) acrylamide or quaternized products of methyl chloride or benzyl chloride are more preferable because they are easily available and inexpensive. (C) As a component, these monomers may be used independently and 2 or more types may be mixed and used for them.

The emulsion according to the present invention can be obtained by emulsion polymerization of the polymerization component in the presence of an emulsifier and / or a protective colloid. The emulsion polymerization may be carried out in water or an organic solvent at about 60 to 120 ° C. for about 1 to 10 hours in the presence of a radical polymerization catalyst as necessary . Examples of the organic solvent include lower alcohol organic solvents such as methanol, ethanol and isopropanol, and oily organic solvents such as benzene, toluene and xylene. These may be used individually by 1 type, or may mix and use 2 or more types. A mixed solvent of a lower alcohol organic solvent and water can also be used as a reaction solvent for the above reaction. Moreover, you may use chain transfer regulators, such as n-dodecyl mercaptan, as needed.

As the radical polymerization catalyst, a water-soluble radical initiator can be used. For example, persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate, peroxides such as hydrogen peroxide, persulfates and peroxidations thereof. A redox polymerization catalyst based on a combination of a product and a reducing agent, a water-soluble azo catalyst such as 2,2′-azobis (2-amidinopropane) dihydrochloride, and an organic peroxide system such as t-butyl hydroperoxide. Can be mentioned. Furthermore, oil-soluble azo-based catalysts such as 2,2′-azobisbutyronitrile and dimethyl 2,2′-azobis- (2-methylpropionate), and oil-soluble organic peroxides such as benzyl peroxide can be used. . In addition, a known chain transfer agent such as alkyl mercaptan may be used in combination as necessary.

Although the usage-amount of (a)-(c) component is not specifically limited, In order to improve water repellency by including about 0.5-20 weight% of (a) component in a polymerization component, it is preferable, especially 1 It is preferable to set it as -5 weight%. In addition, as for the usage-amount of another component, (b) component should just use about 70 to 99.5 weight% normally in a polymerization component, Preferably it is 90 to 98 weight%. (C) When using a component, the usage-amount is about 0-10 weight% normally in a polymerization component, Preferably it is 1-5 weight%. When a cationic monomer is used as the component (c), the amount of the cationic functional group derived from the component (c) in the obtained polymer is more than the amount of the anionic functional group derived from the component (a). Therefore, it is necessary to determine the amount of the component (a) and the amount of the component (c) so as to reduce the amount.

It does not specifically limit as an emulsifier , A well-known thing can be used. Specific examples include anionic surfactants, nonionic surfactants, reactive emulsifiers, and the like. Examples of anionic surfactants include alkyl sulfates, alkylbenzene sulfonates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfates, dialkyl sulfosuccinate esters, alkyl sulfonates, polyoxyethylene alkyl ethers. Sulfosuccinate, polyoxyethylene styryl phenyl ether sulfosuccinate ester salt, polyoxyethylene alkyl ether phosphate ester, α-olefin sulfonate, naphthalene sulfonate formalin condensate, polyoxyethylene alkyl phenyl ether sulfate ester salt, etc. Can be mentioned. Nonionic surfactants include, for example, polyoxyethylene alkyl ethers, polyoxyethylene alkenyl ethers, polyoxyethylene alkyl phenyl ethers, sorbitan higher fatty acid esters, polyoxyethylene sorbitan higher fatty acid esters, polyoxyethylene Examples include higher fatty acid esters, glycerin higher fatty acid esters, and polyalkylene oxide block copolymers. Specific examples include polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene nonylphenyl ether, and polyoxyethylene styryl. Phenyl ether, sorbitan monolaurate, sorbitan trioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene monola , Polyoxyethylene monooleate, monoglyceride oleate, monoglyceride stearate, and polyoxyethylene-polyoxypropylene block copolymers. In addition, as these commercial items, neo-hytenol S70 (Daiichi Kogyo Seiyaku Co., Ltd.) etc. are mentioned as the representative example, for example.

Specific examples of the reactive emulsifier include, for example, a polyoxyethylene alkyl ether having at least one unsaturated double bond moiety in the molecule and a polyoxyethylene alkyl ether having at least one unsaturated double bond moiety in the molecule. A sulfosuccinic acid ester salt, a polyoxyethylene alkyl ether sulfate salt having at least one unsaturated double bond moiety in the molecule, a polyoxyethylene phenyl ether having at least one unsaturated double bond moiety in the molecule, Sulfosuccinic acid ester salt of polyoxyethylene phenyl ether having at least one unsaturated double bond moiety in the molecule, sulfate ester salt of polyoxyethylene phenyl ether having at least one unsaturated double bond moiety in the molecule, At least a saturated double bond moiety in the molecule Polyoxyethylene alkyl phenyl ether having at least one unsaturated double bond moiety in the molecule, sulfooxysuccinate salt of polyoxyethylene alkyl phenyl ether having at least one unsaturated double bond moiety in the molecule, poly having at least one unsaturated double bond moiety in the molecule Sulfuric acid ester salt of oxyethylene alkylphenyl ether, polyoxyethylene aralkyl phenyl ether having at least one unsaturated double bond moiety in the molecule, polyoxyethylene aralkyl phenyl having at least one unsaturated double bond moiety in the molecule Sulfosuccinic acid ester salts of ethers, polyoxyethylene aralkyl phenyl ether sulfates having at least one unsaturated double bond moiety in the molecule, polyoxyethylenes having at least one unsaturated double bond moiety in the molecule Phosphoric acid ester salt of lenalkylphenyl ether, aliphatic or aromatic carboxylate of polyoxyethylene alkylphenyl ether having at least one unsaturated double bond moiety in the molecule, acidic phosphoric acid (meth) acrylic acid ester An emulsifier, an acid anhydride modified product of rosin glycidyl ester acrylate (see JP-A-4-256429), JP-A-63-23725, JP-A-63-240931, JP-A-62-104802 Examples include various emulsifiers described. Furthermore, what replaced the polyoxyethylene in the said reactive emulsifier with the polyoxypropylene or the block copolymerization or random copolymerization of polyoxyethylene and polyoxypropylene is mentioned. Examples of these commercially available products include KAYAMER PM-1 (trade name, manufactured by Nippon Kayaku Co., Ltd.), KAYAMER PM-2 (trade name, manufactured by Nippon Kayaku Co., Ltd.), KAYAMER PM-21 ( Product name, Nippon Kayaku Co., Ltd.), SE-10N (trade name, manufactured by ADEKA Corporation), NE-10 (trade name, manufactured by ADEKA Corporation), NE-20 (trade name, Co., Ltd.) ADEKA), NE-30 (trade name, manufactured by ADEKA Corporation), Adekari Soap SR-10 (trade name, manufactured by ADEKA Corporation), Adeka Soap SR-20 (trade name, manufactured by ADEKA Corporation) ), Adekaria soap ER-20 (trade name, manufactured by ADEKA Corporation), New Frontier A229E (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), New Frontier N117E (trade name, Daiichi Kogyo Seiyaku Co., Ltd.) Made) New Frontier N250Z (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Aqualon RN-10 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Aqualon RN-20 (trade name, Daiichi Kogyo Seiyaku Co., Ltd.) ), Aqualon RN-50 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Aqualon HS-10 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Aqualon KH-05 (trade name, Daiichi Kogyo) Pharmaceutical Co., Ltd.), Aqualon KH-10 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Eminol JS-2 (trade name, manufactured by Sanyo Chemical Industries, Ltd.), Laterum K-180 (trade name, A typical example thereof is Kao Corporation. Among these, it is preferable to use a nonionic surfactant or an anionic surfactant.

The protective colloid is not particularly limited, and a known colloid can be used. Specific examples include those obtained by polymerizing an anionic monomer, a cationic monomer, and other monomers. As the anionic monomer, the component (a) can be used. The cationic monomer is one having at least one cationic functional group and one vinyl group. Specifically, for example, in addition to allylamine, N, N-dimethylaminoethyl (meth) acrylate, N, N -Vinyl monomers having a tertiary amino group such as diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, or their hydrochloric acid, sulfuric acid, acetic acid, etc. Or a quaternary ammonium salt obtained by reacting the tertiary amino group-containing vinyl monomer with a quaternizing agent such as methyl chloride, benzyl chloride, dimethyl sulfate, or epichlorohydrin. A vinyl monomer etc. are mentioned. Examples of monomers other than the anionic monomer and the cationic monomer include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-diisopropyl (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nt-butyl (meth) acrylamide, methyl (meth) acrylate, ethyl (meth) acrylate, (meth ) Acrylic acid alkyl esters such as butyl acrylate, allyl monomers containing allyl groups such as allyl alcohol, N-substituted acrylamide monomers such as isopropylacrylamide, (meth) acrylonitrile, and other bifunctional vinyl monomers As a system Bisacrylamide monomers such as tylene bis (meth) acrylamide, ethylenebis (meth) acrylamide, diacrylate monomers such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, diallylamine, divinylbenzene, etc. Examples of polyfunctional vinyl monomers having three or more vinyl groups include 1,3,5-triacroylhexahydro-S-triazine, triallyl isocyanurate, triallylamine, and tetramethylolmethane tetraacrylate. These polymerization methods may be a known method such as a radical polymerization method. In addition, rosins such as rosin and modified rosin, and salts obtained by neutralizing rosin resins such as partial esters of these rosins with alkali metals, amines, ammonia, etc., basic acid-modified rosin esters and alkyl succinic anhydride alkali salts or Alkenyl succinic anhydride alkali salts, shellac, oxidized starch, polyvinyl alcohol and the like can also be used. These protective colloids may be used alone or in combination of two or more. Although the usage-amount of a protective colloid is not specifically limited, Usually, it is about 1-50 weight part with respect to 100 weight part of polymerization components .

The particle size of the emulsion thus obtained is not particularly limited, but is preferably about 50 to 500 nm. When the particle diameter of the emulsion is smaller than 50 nm, it is difficult to stay on the paper surface, and it is difficult to obtain a satisfactory water repellent effect. When the particle size of the emulsion is larger than 500 nm, it is difficult to maintain the stability of the product.

The emulsion thus obtained can be used as it is as an undercoat coating solution. When used as an undercoat coating solution, the solid content is usually preferably about 0.5 to 5% by weight from the viewpoint of coating properties, etc., and particularly preferably 1 to 3% by weight. Various known additives may be used as necessary. Examples of the additive include an anionic surface sizing agent, oxidized starch, an anionic surface paper strength agent, polyvinyl alcohol, carboxymethyl cellulose, sodium chloride, sodium sulfate, a dye, and an anti-slip agent.

The undercoat coating liquid of the present invention can be applied to a base paper on-machine or off-machine, and as a coating machine, a size press, a film press, a gate roll coater, a shim sizer, a blade coater, a calendar, a bar coater A knife coater, an air knife coater, a curtain coater, or the like can be used. Also, spray coating with two fluids with air is possible.

The coating amount of the undercoat coating solution is selected in the range of 0.01 to 0.5 g / m ^{2 in} terms of solid content. When the coating amount is less than 0.01 g / m ² , the undercoating effect may not be sufficiently exhibited. A drum dryer, a hot air dryer, an infrared dryer or the like can be used for drying the undercoat coating layer regardless of whether it is on-machine or off-machine. It is preferable to adjust the 2-minute Cobb water absorption (JIS P 8140) of the paper after applying the undercoat coating liquid to be in the range of 20 to 60 g / m ² . When the 2-minute Cobb water absorption is less than 20 g / m ² , the water repellent may be repelled when the water repellent is applied, and thus the water repellent may not be applied uniformly. Also, when the 2-minute Cobb water absorption is 60 g / m ² or more, the water repellent penetrates deeply in the Z-axis direction of the paper, so that the barrier effect cannot be obtained and the water repellent effect is not sufficiently exhibited. There is.

  In the present invention, the water repellent applied on the dried undercoat layer is preferably an aqueous emulsion having a wax component as a dispersoid. In this emulsion, the wax-based component serving as a dispersoid may be a single component such as paraffin wax, microcrystalline wax, polyethylene wax, or a blend of these wax components. The dispersoid may be a modified wax component such as maleated petroleum resin, rosin or unsaturated higher alcohol. There are no particular restrictions on the dispersant that contributes to emulsification of the dispersoid, and nonionic emulsifiers, anionic emulsifiers, water-soluble polymers such as polyvinyl alcohol and carboxymethylcellulose, and polymer emulsifiers having self-emulsifying properties such as maleated petroleum resins. Any of these can be used. The surface charge of the dispersoid in the above aqueous emulsion is preferably anionic.

Application of the water repellent and drying of the coating layer can be carried out as usual, and the coating machine and dryer described in Application and drying of the undercoat coating solution are applied and dried with the water repellent. Can also be used. The coating amount of the wax-based water repellent is usually selected in the range of 0.1 to ² g / m ^{2 in} terms of solid content.

  In the undercoating liquid and water repellent of the present invention, as necessary, starches such as oxidized starch, phosphate esterified starch, self-modified starch and amphoteric starch, metal compounds such as zirconium carbonate and sulfate band, carboxymethylcellulose Water-soluble polymers such as celluloses such as cellulose, polyvinyl alcohols, polyacrylamides and sodium alginate can be blended. In this case, it is preferable to mix an anionic one in the undercoat coating liquid and the water repellent. Furthermore, additives such as a surface sizing agent, an antiskid agent, an antiseptic agent, an antirust agent, an antifoaming agent, a viscosity modifier, a dye and a pigment may be added to the undercoat coating solution and the water repellent.

Various types of paper and paperboard can be used as the base paper of the water-repellent paper of the present invention. In particular, the effect is great for papers containing more than 50% by weight of waste paper pulp.
Due to the effect of the present invention, there is almost no sinking of the water repellent caused by the change in surface properties due to an increase in the amount of waste paper pulp. Examples of the water-repellent paper of the present invention include wrapping paper such as kraft paper and pure white roll paper, paperboard board such as manila balls, white balls and chip balls, and paperboards such as liners. %, Especially 80% by weight or more of the liner is the target.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In addition, unless otherwise indicated, the part and% in each example are a weight part and weight%.

(Base paper manufacturing method)
Concentration 3.0% pulp slurry (corrugated cardboard 100%, freeness 300ml CSF, ash content in paper 11.0%), aluminum sulfate 1.0% to absolutely dry pulp, rosin emulsion sizing agent (trade name: Size Pine N815) , Arakawa Chemical Industries, Ltd.) 0.2% with respect to the absolutely dry pulp, diluted to 1.0% slurry with white water, and then dried paper strength enhancer (trade name: Polystron F6, Arakawa) Chemical Industry Co., Ltd.) was added 0.2% to the absolutely dry pulp. The pH of the pulp slurry at this time was 6.8. Dehydrated using a tapi sheet machine, 5 kg / cm ²
Press for 2 minutes. Subsequently, it dried for 4 minutes at 105 degreeC with a rotary dryer, and 23 degreeC and 55% R. H. By adjusting the humidity for 24 hours under the above conditions, a paper having a basis weight of 150 g / m ² and a 2-minute bump water absorption of 72 g / m ² was obtained.

(Manufacturing method of undercoat coating liquid)
Production Example 1
In a flask equipped with a stirrer, a condenser, a nitrogen inlet tube and a thermometer, 714 parts of water and 175 parts of a sodium salt of octadecyl succinic anhydride (an aqueous solution having a nonvolatile content of 34% and a pH of 9.0) as a protective colloid 20% by weight based on the total amount of monomers), 297 parts of styrene, 4 parts of acrylic acid, 0.75 part of N-dodecyl mercaptan, 3.5 parts of 48% caustic soda (100 mol% neutralized with respect to acrylic acid) and A mixture of 3 parts of an anionic surfactant (AQUALON RN50: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was charged. After sufficiently replacing oxygen in the reaction system with nitrogen, the temperature of the mixture was raised to 70 ° C., and then a radical polymerization initiator (an aqueous solution in which 6 parts of ammonium persulfate was dissolved in 15 parts of water) was added to the reaction vessel. . Next, after emulsion polymerization for 20 minutes, the temperature was raised to 80 ° C., and the polymerization reaction was allowed to proceed in the temperature range of 80 to 85 ° C. for 2 hours. Thus, an emulsion composition having a pH of 8.6, a solid content concentration of 30.2%, and a viscosity of 15 mPa · s / 25 ° C. was obtained.

Production Examples 2-6
An emulsion composition was obtained in the same manner as in Production Example 1 except that the composition, emulsifier and protective colloid were changed to those shown in Table 1. The results are shown in Table 1.

Production Example 7
In a flask equipped with a stirrer, a condenser tube, a nitrogen inlet tube and a thermometer, 713 parts of water and 28% of polybasic acid-modified rosin ester (trade name “Marquide No. 32” manufactured by Arakawa Chemical Industries, Ltd.) as a protective colloid 293 parts of an aqueous solution having a non-volatile content of 20% and a pH of 9.0 dissolved by adding an equal amount of ammonia water (20% by weight based on the total amount of vinyl monomers), 30 parts of α-methylstyrene, 2-ethylhexyl 210 parts of acrylate, 54 parts of benzyl chloride quaternized product of N, N-dimethylaminoethyl methacrylate, 6 parts of acrylamide, 0.75 part of N-dodecyl mercaptan and an anionic surfactant (Hitenol LA10: Daiichi Kogyo Seiyaku ( (Mixed) 3 parts of the mixture was charged. After sufficiently replacing oxygen in the reaction system with nitrogen, the temperature of the mixture was raised to 70 ° C., and then a radical polymerization initiator (an aqueous solution in which 6 parts of ammonium persulfate was dissolved in 15 parts of water) was added to the reaction vessel. . Next, after emulsion polymerization for 20 minutes, the temperature was raised to 80 ° C., and the polymerization reaction was allowed to proceed in the temperature range of 80 to 85 ° C. for 2 hours. Thus, an emulsion composition having a pH of 8.7, a solid content concentration of 30.3%, and a viscosity of 14 mPa · s / 25 ° C. was obtained.

Production Example 8
4. In a flask equipped with a stirrer, condenser, nitrogen inlet tube and thermometer, 106 parts of isopropyl alcohol, 235 parts of styrene, 80 parts of N, N-dimethylaminoethyl methacrylate, dimethyl-2,2-azobisisobutyrate The monomer mixture obtained by mixing 6 parts was heated to 80 ° C. and stirred for 3 hours while stirring under a nitrogen stream. Further, 3.2 parts of perbutyl O (manufactured by Nippon Oil & Fats Co., Ltd.) was charged and kept at 80 ° C. for 4 hours. Subsequently, 980 parts of ion-exchanged water and 24.8 parts of acetic acid were charged and neutralized. Further, 38.8 parts of epichlorohydrin was charged at 55 ° C. and kept warm for 3 hours. The solid content concentration of the copolymer was adjusted to 20% by weight to obtain a copolymer aqueous solution having a viscosity at 25 ° C. of 35 mPa · s.

Production Example 9
While introducing nitrogen into a flask equipped with a stirrer, a cooling tube, a nitrogen introducing tube and a thermometer, 400 parts of soft water and 300 parts of isopropyl alcohol were charged, and the system was heated to 80 ° C. while stirring. Next, a vinyl monomer mixed solution in which 210 parts of styrene, 30 parts of α-methylstyrene, 75 parts of methacrylic acid, and 0.75 part of N-dodecyl mercaptan were mixed with the system, and perbutyl O (manufactured by NOF Corporation) 6 A polymerization initiator aqueous solution having a part dissolved in 120 parts of water was dropped into the system over about 3 hours, and then the system was kept warm for 2 hours to complete the reaction. Thereafter, isopropyl alcohol was distilled off, and after cooling, 81 parts of a 48% potassium hydroxide aqueous solution (100 mol% with respect to methacrylic acid) was added and diluted with water to adjust the concentration of the copolymer to 25%. A copolymer aqueous solution having a viscosity at 25 ° C. of 500 mPa · s was obtained.

The particle sizes in Table 1 were measured using a laser particle size analysis system LPA-3000 / 3100 (manufactured by Otsuka Electronics Co., Ltd.).

In the table, AA is acrylic acid, MAA is methacrylic acid, St is styrene, BMA is butyl methacrylate, BA is butyl acrylate, αMeSt is α-methylstyrene, 2EHA is 2-ethylhexyl acrylate, AM is acrylamide, AN is acrylonitrile, DML is Benzyl chloride quaternized product of N, N-dimethylaminoethyl methacrylate, DM is N, N-dimethylaminoethyl methacrylate, ODSA-Na is a sodium salt of octadecyl succinic anhydride, Aqualon RN50 (trade name: Daiichi Kogyo Seiyaku Co., Ltd. )): Reactive emulsifier, Neo Haitenol S70 (trade name: Daiichi Kogyo Seiyaku Co., Ltd.): Low molecular weight emulsifier, Marquide No32 (trade name: Arakawa Chemical Industries, Ltd.): Polybasic acid-modified rosin Esther, Hiparatech PR (Product name: Sun Made Shellac Industry Co., Ltd.): polybasic acid-modified rosin ester, Marukido 3002: manufactured (trade name by Arakawa Chemical Industry Co.): represents a polybasic acid-modified rosin ester (maleic acid-modified rosin pentaerythritol ester). The numerical values of the components (a), (b), and (c) represent parts by weight (solid content) with respect to 100 parts by weight of the vinyl monomer constituting the basic polymer. Various emulsifiers in the table were used in an amount of 1 part by weight (solid content) with respect to 100 parts by weight of the vinyl monomer constituting the basic polymer. The various protective colloids in the table were used in an amount of 20 parts by weight (solid content) based on 100 parts by weight of the vinyl monomer constituting the basic polymer.

(Method for producing water-repellent paper)
A coating solution obtained by diluting Production Examples 1 to 9 with tap water to 1.0% was applied to the base paper with No. 1 to No. 2 in the base paper. After coating with an 8-bar coater, drying was performed at 105 ° C. for 1 minute using a circulating dryer and 120 ° C. for 30 seconds using a rotary dryer. The resulting coated paper was 23 ° C., 55% R.D. H. After adjusting the humidity for 24 hours under the above conditions, the water absorption degree of the bumps was measured according to JIS P8140, and the slip angle was measured according to the inclination method of JIS P8147. The measurement results are shown in Table 2.
Next, a water repellent (trade name: Size Pine W116H, manufactured by Arakawa Chemical Industry Co., Ltd.) is applied to the paper coated as described above in amounts of 0.15 g / m ² and 0.3 g / m ² and 0. .45 g / m ² Coating was performed with an 8-bar coater, and drying was performed at 105 ° C. for 1 minute using a circulating dryer and 120 ° C. for 30 seconds using a rotary dryer to obtain water-repellent paper.

Water was added to the back of each water-repellent paper obtained. It was coated with a 10 bar coater, dried at 120 ° C. for 2 minutes in a rotary dryer, and then 23 ° C., 55% R.D. H. The water repellency was measured after conditioning for 24 hours under the above conditions. The results are shown in Table 2. The water repellency was measured using JAPAN Tappi No. 68.

The amount of static electricity on the paper surface was measured using a coulomb meter MODEL NK-1001 (manufactured by Kasuga Denki Co., Ltd.) after drying for 5 minutes with a circulating dryer at 105 ° C. and rubbing the paper surfaces 10 times.

＊ 撥水度（Ｒ）；Ｒ１が最も撥水性が低く、Ｒ１０が最も高い。

* Water repellency (R); R1 has the lowest water repellency and R10 has the highest.

As can be seen from the results shown in Table 2, Production Example 7 (Cationic Emulsion) and Production Example 8 (Cation) were obtained by using a water-repellent primer coating solution containing an anionic polymer (A) emulsion. Water-soluble polymer) and good water repellency in comparison with known undercoat coating solutions such as Production Example 9 (anionic water-soluble polymer that is not an emulsion).

Claims (6)

(Meth) acrylic acid and / or (meth) allylsulfonic acid (a), (meth) acrylic acid alkyl esters and / or styrenes (b), and optionally (meth) acrylamide and / or N-substituted An undercoat coating solution for water repellent containing an emulsion obtained by emulsion polymerization of a polymerization component comprising acrylamides (c) in the presence of an emulsifier and / or a protective colloid . Polymerization component, (a) a water repellent for undercoat coating solution according to claim 1, wherein the component containing 0.5 to 20 wt%. The undercoat coating liquid for water repellent according to claim 1 or 2, wherein the polymerization component contains 70 to 99.5% by weight of component (b). The undercoat coating solution for a water repellent according to any one of claims 1 to 3, wherein the polymerization component contains 0 to 10% by weight of the component (c). Claim 1 repellent paper having a coating layer and the water repellent layer obtained by using the water repellent agent for undercoat coating solution according to any one of the 4. It has the process of applying and drying a water repellent on the provided coating layer, the process of applying and drying the undercoat coating liquid for water repellent in any one of Claims 1-4 to a base paper A method for producing water-repellent paper.