JP2015063786A - Emulsion sizing agent for paper making - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emulsion sizing agent for paper making having less production of an aggregate by interaction with cationic substances such as calcium existing in a papermaking system, having stability of pH and hardness of water for papermaking in a wide range, and excellent in sizing property.SOLUTION: An emulsion sizing agent is provided as a dispersion prepared from a dehydration condensate (A), obtained by a dehydration condensation of a trivalent or tetravalent carboxylic acid (a1) and at least one kind of compound (a2) selected from a group consisting of monovalent aliphatic alcohol (a2-1) having an alkyl group or an alkenyl group having 6 to 22 carbon atoms and aliphatic amine (a2-2) having an alkyl group and/or an alkenyl group having 6 to 22 carbon atoms, by using, as a dispersant, (meth)acryl amide-based copolymer (B) obtained by polymerizing a monomer containing (meth)acryl amide (b1) of 50 to 90 mol%, a carboxyl group-containing monomer (b2) of 2 to 40 mol%, a sulfo group-containing monomer (b3) of 0.1 to 10 mol% and a hydrophobic monomer (b4) of 2 to 30 mol%.

Description

The present invention relates to an emulsion sizing agent for papermaking.

In recent years, in the paper manufacturing process, (1) increase in papermaking pH due to the use of calcium carbonate, a low-cost filler, (2) increase in the ratio of used paper, and (3) papermaking closed to reduce papermaking wastewater. It is changing to the situation where the effect of the medicine is hard to express.

Regarding the pH of the papermaking environment, the rosin type sizing agent, which has been conventionally used as an internal sizing agent, must be used in the acidic range, and the size effect is reduced in the weakly acidic to alkaline pH range.

On the other hand, so-called neutral sizing agents represented by alkenyl succinic anhydride-based sizing agents and ketene dimer-based sizing agents can be used in a wide pH range from weakly acidic to alkaline due to their reactivity with cellulose.

On the other hand, the neutral sizing agent has a defect that its stability is poor, that is, it has poor storage stability, mechanical stability, chemical stability and the like as an aqueous dispersion. Furthermore, among the above neutral sizing agents, the ketene dimer sizing agent requires a considerable period of time until the size effect of the resultant paper reaches the target value, and a phenomenon of so-called sizing effect is recognized. Therefore, it is disadvantageous in terms of quality control of the obtained paper product.

Therefore, it can be applied in a wide pH range from the acidic range to the neutral range, has no rise in size effect, and is a specific polybasic carboxylic acid as a sizing agent with excellent storage stability, mechanical stability, and chemical stability. An emulsion sizing agent in which a dehydration condensate composed of an acid component and a specific alcohol or amine component is dispersed in water has been reported (Patent Document 1, Patent Document 2 and Patent Document 3).
However, these emulsion-type sizing agents have not yet solved the problems caused by the above (2) and (3). In other words, an increase in the hardness of papermaking water due to an increase in dissolved calcium ions causes the aggregation and destruction of emulsion sizing agent particles, which significantly inhibits the dispersion and fixing of the sizing agent to pulp fibers and reduces the sizing effect. However, it did not respond to various changes in water hardness for papermaking in recent years.

JP 59-21797 A JP 61-70094 JP-A-5-339896

As described above, the paper manufacturing environment has been changed in various ways, and the water hardness for papermaking is in the range of 5 to 200 ° dH, varies depending on the papermaking machine, and the papermaking pH also varies. Therefore, even under such papermaking conditions, the papermaking system In particular, there is a need for an emulsion-type sizing agent that is excellent in dilution and dispersion stability, has a stable size effect, and does not generate aggregates. In the present invention, the mechanical stability is good, the formation of aggregates due to the interaction with a cationic substance such as calcium present in the papermaking system is small, and the hardness of the papermaking water is in a wide range from low hardness to high hardness. An object of the present invention is to provide a papermaking emulsion sizing agent having stability and excellent size properties.

The present inventors have intensively studied to solve the above problems. As a result, a dehydration condensate of a specific polyvalent carboxylic acid and an aliphatic and specific aliphatic amine was used as a component of the sizing agent, and this was dispersed in a copolymer having hydrophilic (meth) acrylamide as the main component. It has been found that the above-mentioned problems can be solved by using the obtained emulsion sizing agent.

That is, the present invention relates to a trivalent or tetravalent carboxylic acid (a1), a monovalent aliphatic alcohol (a2-1) having an alkyl group or an alkenyl group having 6 to 22 carbon atoms, and 6 to 22 carbon atoms. Dehydration condensates (A) and (meth) acrylamides obtained by dehydration condensation of at least one compound (a2) selected from the group consisting of aliphatic amines (a2-2) having an alkyl group and / or alkenyl group b1) 50 to 90 mol%, carboxyl group-containing monomer (b2) 2 to 40 mol%, sulfo group-containing monomer (b3) 0.1 to 10 mol%, and hydrophobic monomer ( The invention relates to a papermaking emulsion sizing agent comprising a (meth) acrylamide copolymer (B) obtained by polymerizing a monomer containing 2 to 30 mol% of b4).

The papermaking emulsion sizing agent of the present invention has a good size effect in the acidic to neutral range. In addition, it has good mechanical stability and stability in a wide range of water hardness for papermaking from low hardness to high hardness (hard water dilution stability), and can sufficiently cope with the recent closure of papermaking systems. .

The emulsion sizing agent for papermaking of the present invention is a monovalent having a trivalent or tetravalent carboxylic acid (a1) (hereinafter referred to as component (a1)) and an alkyl group and / or alkenyl group having 6 to 22 carbon atoms. Aliphatic alcohol (a2-1) (hereinafter referred to as component (a2-1)) and aliphatic amine (a2-2) having an alkyl group and / or alkenyl group having 6 to 22 carbon atoms (hereinafter referred to as component ( dehydrated condensate (A) (hereinafter referred to as component (A)) obtained by dehydrating condensation of at least one compound (a2) (hereinafter referred to as component (a2)) selected from the group consisting of a) It is characterized by containing.

The component (a1) is not particularly limited as long as it is a trivalent or tetravalent carboxylic acid, and a known one can be used. Specific examples include citric acid, tricarballylic acid, t-aconitic acid, trimellitic acid, pyromellitic acid, and butanetetracarboxylic acid. In addition, the carboxyl group which these trivalent or tetravalent carboxylic acid has may be an acid anhydride. The component (a1) may be a trivalent carboxylic acid or an ester or amide of a tetravalent carboxylic acid that can react with the component (a2) by transesterification or amide exchange reaction. These may be used alone or in combination of two or more. As the component (a1), citric acid is preferable because it has a large effect of improving water resistance and is relatively inexpensive.

As a component (a2-1), if it is a monovalent | monohydric aliphatic alcohol which has a C6-C22 alkyl group and / or an alkenyl group, it will not specifically limit and a well-known thing can be used. Component (a2-1) may be a saturated aliphatic alcohol or an unsaturated aliphatic alcohol containing a carbon-carbon unsaturated bond in the molecule. Specifically, examples of the saturated aliphatic alcohol include 2-ethylhexyl alcohol, octyl alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and behenyl alcohol. Examples of the unsaturated aliphatic alcohol include oleyl alcohol. These may be used alone or in combination of two or more. Component (a2-1) is preferably palmityl alcohol, stearyl alcohol, or a mixture thereof from the viewpoint of improving water resistance.

As a component (a2-2), if it is an aliphatic amine which has a C6-C22 alkyl group and / or an alkenyl group, it will not specifically limit, A well-known thing can be used. The amine is preferably a primary amine or a secondary amine. Examples of the primary amine include octylamine, decylamine, stearylamine, and examples of the secondary amine include dioctylamine, didecylamine, distearylamine, di-cured tallow amine, and dibehenylamine. These may be used alone or in combination of two or more.
As the component (a2), the component (a2-1) or the component (a2-2) may be used alone or in combination. Moreover, a component (a2-2) is preferable among the components (a2) from a point of improvement in water resistance, and among them, distearylamine and di-cured tallowamine are more preferable.

The reaction of component (a1) and component (a2) can be dehydration-condensed under the reaction conditions of a reaction in which a normal carboxylic acid and an alcohol are reacted to esterify, or a reaction in which a carboxylic acid and an amine are reacted to amid. Specifically, for example, considering the boiling point of each component, dehydration condensation may be performed while stirring at about 110 to 180 ° C. for about 1 to 24 hours under normal pressure or reduced pressure. Moreover, you may use a well-known basic or acidic catalyst and a solvent as needed. The reaction may be carried out by azeotropic dehydration by using a solvent such as benzene, toluene or xylene.

Even when a lower ester of a carboxylic acid or an amide of a carboxylic acid is used as the starting material as the component (a1), the reaction can be similarly carried out. In transesterification, it is preferable to use a transesterification reaction catalyst. Specific examples include di-n-butyltin oxide and p-toluenesulfonic acid.

The amount of component (a1) and component (a2) used is usually such that at least one carboxyl group of component (a1) forms an ester bond and / or an amide bond with component (a2) and component (a1) It is preferable that at least one carboxyl group remains unreacted. When a trivalent carboxylic acid is used as the component (a1), the hydroxyl group or amino group of the component (a2) is 1 to 2 equivalents relative to 3 equivalents of the carboxyl group of the component (a1). To do. When a tetravalent carboxylic acid is used as the component (a1), the hydroxyl group or amino group of the component (a2) is 2 to 3 equivalents relative to 4 equivalents of the carboxyl group of the component (a1). To do. The remaining carboxyl group may exist as it is, or may form a carboxyl group salt. Examples of the carboxyl group salt include alkali metal salts such as sodium and potassium, and ammonium salts such as ammonia, methylamine and ethanolamine.

The component (A) thus obtained usually has a melting point of 100 ° C. or lower, preferably 70 ° C. or lower.

In the emulsion sizing agent for papermaking of the present invention, 50 to 90 mol% of (meth) acrylamide (b1) and 2 to 40 mol% of the carboxyl group-containing monomer (b2) as a dispersant are added to the component (A). A (meth) acrylamide system obtained by polymerizing a monomer containing 0.1 to 10 mol% of the sulfo group-containing monomer (b3) and 2 to 30 mol% of the hydrophobic monomer (b4) A copolymer (B) (hereinafter referred to as component (B)) is used for dispersion in water. Moreover, as a component (B), it is more preferable to contain 0.1-5 mol% of polyfunctional monomers (b5) as a monomer component.

(Meth) acrylamide (b1) (hereinafter referred to as component (b1)) refers to acrylamide and / or methacrylamide. The component (b1) is used for imparting hydrophilicity to the dispersant. The amount used is in the range of 50 to 90 mol%, preferably 60 to 85 mol% of the total molar sum of the monomers constituting component (B). When the amount of the component (a1) used exceeds 90 mol%, the resulting emulsion particles cannot be refined, and by making the amount 85 mol% or less, the emulsion particles can be more stably refined.

The carboxyl group-containing monomer (b2) (hereinafter referred to as component (b2)) is used for maintaining emulsification. The amount used is in the range of 2 to 40 mol%, preferably 3 to 20 mol% of the total molar sum of the monomers constituting component (B). When the usage-amount of a component (b2) exceeds 40 mol%, emulsification power becomes weak. As the component (b2), (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid or salts thereof can be used. It does not specifically limit as a salt, A well-known thing can be used. Specific examples include alkali metal salts such as sodium salt and potassium salt, and ammonium salts such as ammonia, methylamine and ethanolamine. These may be used alone or in combination of two or more. Of these, itaconic acid or a salt thereof is particularly preferable.

The sulfo group-containing monomer (b3) (hereinafter referred to as the component (b3)) is used for imparting strong anionicity to the component (B) that is a dispersant. The amount used thereof is in the range of 0.1 to 10 mol%, preferably 0.5 to 5 mol% of the total molar sum of the monomers constituting component (B). Use of the component (b3) having a relatively strong acidity in addition to the component (b2) as the anionic component of the component (B) is preferable because it can improve the hard water dilution stability of the emulsion. When the amount of component (b3) used is less than 0.1 mol%, the fixing ability of the resulting emulsion sizing agent tends to be reduced due to anionic decrease. In addition, when the amount of component (b3) used exceeds 10 mol%, the cohesive force of the resulting emulsion sizing agent becomes too strong, so that the distribution on paper tends to be uneven and the size effect tends to decrease.

Examples of the component (b3) include styrene sulfonic acid, vinyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, and (meth) allyl. Sulfonic acid-based monomers such as sulfonic acid and / or sulfuric acid ester of hydroxyethyl (meth) acrylate, sulfuric acid ester of hydroxypropyl (meth) acrylate, sulfuric acid ester of polyoxyalkylene (meth) acrylate, polyoxyethylene alkylpropenyl Examples thereof include sulfate monomers such as ether sulfates, and salts thereof. The salt is not particularly limited, and examples thereof include alkali metal salts such as sodium and potassium, ammonium salts, amine salts such as trimethylamine, triethylamine, dimethylamine, diethylamine, monomethylamine, and monoethylamine. These can be used singly or in combination of two or more. Among them, it is most preferable to use 0.5 to 5 mol% of (meth) allylsulfonic acid or a salt thereof.

The hydrophobic monomer (b4) (hereinafter referred to as component (b4)) is used to impart hydrophobicity to component (B), which is a dispersant. The amount of component (b4) used is 2 to 30 mol%, preferably 5 to 20 mol% of the total molar sum of the monomers constituting component (B). Emulsification becomes easy by making a component (b4) into 2-30 mol%.

Component (b4) includes (meth) acrylic acid ester having 1 to 20 carbon atoms such as ethyl (meth) acrylate, methyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, and styrene. , Styrenes such as α-methylstyrene, styrene monomers of styrene compounds having an alkyl group having 1 to 4 carbon atoms on the aromatic ring of these styrenes, vinyl acetates such as vinyl acetate and vinyl propionate And an α-olefin having 6 to 22 carbon atoms, an alkyl vinyl ether having 1 to 22 carbon atoms, vinyl pyrrolidone and the like. Among these, (meth) acrylic acid esters of alkyl alcohols having 1 to 12 carbon atoms are particularly preferred from the viewpoint of emulsification.

The polyfunctional monomer (b5) (hereinafter referred to as component (b5)) is not particularly limited as long as it is a polyfunctional monomer having two or more radically polymerizable functional groups, and a known one can be used. . The amount of component (b5) used is preferably 0.1 to 5 mol% of the total molar sum of the monomers constituting component (B). By using the component (b5), a branched (crosslinked) structure can be introduced into the component (B). Specific examples of the component (b5) include polyfunctional (meth) acrylamides such as methylenebisacrylamide, hexanediol diacrylate, 1,9-nonanediol diacrylate, tetraethylene glycol diacrylate, and hexaethylene glycol. Multifunctional such as diacrylate, tripropylene glycol diacrylate, dicyclopentanyl diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, 1,3,5-triacroylhexahydro-1,3,5-triazine Examples include (meth) acrylates, aromatic polyvinyl compounds such as divinylbenzene, and the like. These may be used alone or in combination of two or more. As component (b5), 1,9-nonanediol diacrylate, tetraethylene glycol diacrylate, hexaethylene glycol diacrylate, tripropylene glycol diacrylate, dicyclopentanyl diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate Acrylate is more preferred.

As the monomer constituting the component (B) of the present invention, a cationic vinyl monomer (b6) (hereinafter referred to as component (b6)) can be further used. By using the component (b6), a high size effect can be secured in a wide range of pH and hardness of papermaking water. The component (b6) refers to a monomer having a cationic group and a radical polymerizable functional group such as a vinyl monomer having a tertiary amino group or a quaternary amino group. The amount of component (b6) used is preferably from 0.1 to 25 mol%, more preferably from 1 to 24 mol%, based on the total molar sum of the monomers constituting component (B). Examples of vinyl monomers having a tertiary amino group include dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and diethylaminopropyl (meth) acrylate. Dialkylaminoalkyl (meth) acrylate, and dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, etc. include dialkylaminoalkyl (meth) acrylamide etc. It is done.
Examples of the vinyl monomer having a quaternary amino group include those obtained by reacting the vinyl monomer component having a tertiary amino group with a quaternizing agent. It can also be obtained by reacting a copolymer obtained using the vinyl monomer component having the tertiary amino group with a quaternizing agent. Examples of the quaternizing agent include conventionally known ones such as oxides, organic halides, dimethyl sulfate, and diethyl sulfate. Specific examples of the oxides include alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide, and styrene oxide. Examples of the organic halide include methyl chloride, ethyl chloride, benzyl chloride, epichlorohydrin, glycidyltrimethylammonium chloride, and 3-chloro-2-hydroxyammonium chloride.

Moreover, as a monomer of the component (B) of the present invention, if necessary, a nitrile monomer such as (meth) acrylonitrile within a range of 20 mol% or less of the total molar sum of monomers; hydroxy (meth) acrylate Contains hydroxyl groups such as ethyl, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate; glycerol di (meth) acrylate, pentaerythritol mono (meth) acrylate, (meth) allyl alcohol, etc. Monomer: Polyoxyalkylene (meth) acrylic acid ester, polyoxyalkylene glycerin (meth) acrylic acid ester, polyoxyalkylene monoalkyl (meth) acrylic acid ester, polyoxyalkylene (meth) allyl ether, polyoxyalkylene glycerin ( Motor) may be used a polyoxyalkylene group-containing monomers such as allyl ether.

As a manufacturing method of a component (B), various well-known methods, such as solution polymerization, emulsion polymerization, suspension polymerization, can be employ | adopted, and it can obtain easily by copolymerizing the said monomer. In the case of solution polymerization, a solvent such as isopropyl alcohol, ethyl alcohol, or methyl isobutyl ketone can be used. The emulsifier used in the emulsion polymerization method is not particularly limited, and various surfactants can be used. Examples of the anionic surfactant include dialkyl sulfosuccinate, alkane sulfonate, α-olefin sulfonate, polyoxyethylene alkyl ether sulfosuccinate, polyoxyethylene styryl phenyl ether sulfosuccinate, naphthalene sulfonate. Formalin condensates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkylphenyl ether sulfates and the like can be exemplified. Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene styryl phenyl ethers, polyoxyethylene sorbitan fatty acid esters and reactive surfactants in which vinyl, allyl, or propenyl groups are introduced into these surfactants. It can be illustrated. These surfactants can be used by appropriately selecting one kind or two or more kinds, and the amount used is usually about 0.1 to 10% by weight with respect to all charged monomers. In addition, the polymerization initiator used in the polymerization is not particularly limited, and various types such as persulfates, peroxides, azo compounds, redox initiators can be used, and are known for adjusting the molecular weight. Chain transfer agents such as isopropyl alcohol, carbon tetrachloride, ethylbenzene, isopropylbenzene, cumene, thioglycolic acid ester, alkyl mercaptan, 2,4-diphenyl-4-methyl-1-pentene, and the like can also be used as appropriate.

Although content of the component (B) in the emulsion size agent for papermaking of this invention is not specifically limited, About 0.1-50 weight% normally in conversion of solid content with respect to a component (A), Preferably it is 1-30 weight %. When the amount is less than 0.1% by weight, it is difficult to maintain sufficient emulsifying properties, and when the amount exceeds 50% by weight, the significance of adding excessively is not recognized, and neither is preferable.

By using the component (B), water dispersion of the component (A) is stabilized, and a high size effect can be ensured in a wide range of pH and hardness of papermaking water.

As a method for dispersing component (A) in water with component (B), that is, a method for producing an emulsion sizing agent, either a high-pressure emulsification method or an inversion emulsification method can be employed.

In the case of the high-pressure emulsification method, the component (A) that forms the dispersed phase is melted or dissolved in a solvent such as benzene or toluene, and then the component (B) is added in the above-mentioned use ratio and simultaneously with warm water. After emulsification using a high-pressure emulsifier, an aqueous dispersion can be obtained as it is or by distilling off the solvent. In addition, in the case of the inversion method, the components (A) and (B), which are solid components, are sufficiently kneaded, and then melted and gradually added with warm water while stirring to invert the solvent and special emulsification. An aqueous dispersion can be obtained without using an apparatus. The solid content concentration of the aqueous dispersion is not particularly limited, but is usually 10 to 50% by weight, and it can be diluted with water as necessary.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “%” and “part” mean “% by weight” and “part by weight” unless otherwise specified.

[Synthesis example of component (A)]
Production Example 1
Citric acid monohydrate 210 parts (1 mole) and stearyl alcohol (trade name “NAA-46”, stearyl alcohol / palmityl alcohol = 85/15 (%), manufactured by NOF Corporation) 532 parts (2 moles) The mixture was heated to 160 ° C. while distilling off the generated water to the outside of the reaction system, and the dehydration condensation reaction was continued at the same temperature for 1.5 hours. The reaction product was cooled to obtain a wax-like dehydrated condensate containing a diester compound as a main component. The dehydration condensate had a melting point of 48 to 51 ° C. and an acid value of 78.7 mgKOH / g.

Production Example 2
Citric acid monohydrate 210 parts (1 mol) and di-cured tallow amine (trade name “Armin 2HT” manufactured by Lion Akzo Co., Ltd .: alkyl chain length ratio C16 / C18 = 40/60) 1000 parts (2 mol) And 1252 parts of toluene were mixed, and the dehydration condensation reaction was continued for 20 hours under reflux of toluene. Toluene was distilled off from the reaction mixture under reduced pressure to obtain a wax-like dehydrated condensate containing a diamide compound as a main component. The dehydration condensate had a constant melting point of 52 to 56 ° C. and an acid value of 55.7 mgKOH / g.

Production Example 3
176 parts (1 mol) of tricarballylic acid and 532 parts (2 mol) of stearyl alcohol (trade name “NAA-46”) were mixed, heated to 160 ° C., and the dehydration condensation reaction was continued for 1.5 hours at the same temperature. . The reaction product was cooled to obtain a wax-like dehydrated condensate containing a diester compound as a main component. The dehydration condensate had a melting point of 48 to 51 ° C. and an acid value of 78.7 mgKOH / g.

Production Example 4
176 parts (1 mol) of tricarballylic acid, 1000 parts (2 mol) of di-cured tallow amine (trade name “Armin 2HT”) and 1252 parts of toluene were mixed, and the reaction was continued for 20 hours under reflux of toluene. Toluene was removed from the reaction mixture under reduced pressure to obtain a wax-like dehydrated condensate containing a diamide compound as a main component. The dehydration condensate had a constant melting point of 52 to 56 ° C. and an acid value of 53.0 mgKOH / g.

Production Example 5
174 parts (1 mole) of t-aconitic acid, 1000 parts (2 moles) of di-cured tallow amine (trade name “Armin 2HT”) and 1252 parts of toluene were mixed, and the reaction was continued for 20 hours under reflux of toluene. . Toluene was distilled off from the reaction mixture under reduced pressure to obtain a wax-like dehydrated condensate containing a diamide compound as a main component. The dehydration condensate had a constant melting point of 52 to 56 ° C. and an acid value of 53.0 mgKOH / g.

[Synthesis Example of Component (B) (Dispersant)]
Production Example 6
In a reactor equipped with a stirrer, thermometer, reflux condenser and nitrogen introduction tube in a 1 l four-necked flask, 31.4 parts (1.5 mol%) of hexaethylene glycol diacrylate and 287.6 parts of acrylamide (75 .4 mol%), itaconic acid 59.3 parts (8.5 mol%), sodium methallylsulfonate 25.4 parts (3.0 mol%), 2-ethylhexyl acrylate 29.6 parts (3.0 mol) %), 77.3 parts (8.6 mol%) of cyclohexyl methacrylate, 711.3 parts of ion-exchanged water, 784.9 parts of isopropyl alcohol, 2.51 parts of 2-mercaptoethanol (total amount of polymerization components) The mixture was heated to 50 ° C. under nitrogen gas bubbling with stirring. As a polymerization initiator, 11.0 parts of ammonium persulfate (APS) (0.9 mol% based on the total number of moles of polymerization components) was added, and the temperature was raised to 80 ° C. and held for 180 minutes. Next, isopropyl alcohol was distilled off by blowing water vapor, and ion exchange water was added to obtain a copolymer aqueous solution having a solid content of 24%. The viscosity of the 24% aqueous solution was 1040 mPa · s. The viscosity was measured with a Brookfield rotational viscometer (manufactured by TOKIMEC, VISCOMETER) (hereinafter, the viscosity measurement conditions are the same).

Production Examples 7 to 32, Comparative Production Examples 1 to 9
Except having changed the compounding composition of each monomer used in manufacture example 6 as shown in Table 1, it carried out by the same method and obtained the dispersing agent which is a copolymer solution with a solid content of 24%.

In the table, AM is acrylamide, IA is itaconic acid, MAA is methacrylic acid, SMAS is methallylsulfonic acid sodium salt, NaSS is sodium styrenesulfonate, 2EHA is 2-ethylhexyl acrylate, CHMA is cyclohexyl methacrylate, and 6EGA is hexaethylene. Glycol diacrylate, MBAA is methylenebisacrylamide, DM is dimethylaminopropylmethacrylamide, and DML is an ammonium salt obtained by quaternizing DM with benzyl chloride.

The numerical values of the components (b1) to (b6) in the table represent the mol% of each component relative to the total number of moles of the polymerization component, and the unit of viscosity represents mPa · s.

Comparative production example 10
A reactor equipped with a stirrer, thermometer, reflux condenser and nitrogen inlet tube in a 1 l four-necked flask was charged with 31.4 parts of dimethylaminoethyl methacrylate, 85.3 parts of a 50% aqueous solution of acrylamide, 20.8 parts of styrene. Part, 100.6 parts of ion-exchanged water, 143.3 parts of isopropyl alcohol, and 0.6 part of n-dodecyl mercaptan were adjusted to pH 4.5 with a 20% aqueous acetic acid solution. The mixture was heated to 60 ° C. in a nitrogen gas atmosphere while stirring. As a polymerization initiator, 2.3 parts of a 5% aqueous solution of ammonium persulfate was added, the temperature was raised to 80 ° C. and maintained for 1.5 hours, and then 0.7 part of a 5% aqueous solution of ammonium persulfate was added. Furthermore, after maintaining for 1 hour, 100 parts of ion-exchanged water was added, and isopropyl alcohol was distilled off. After completion of the distillation, ion exchange water was added to obtain an aqueous solution containing 20% of the polymer. It was 340 mPa · s of the copolymer.

Comparative Production Example 11
Into a reactor equipped with a stirrer, thermometer, reflux condenser and nitrogen introduction tube in a 1 l four-necked flask, 57 parts of vinyl pivalate, 20 parts of methacrylic acid and methyl chloride 4 of N, N-dimethylaminopropyl acrylamide 20 parts of the graded product, 3 parts of potassium persulfate and 400 parts of water were mixed, heated, and reacted at 80 ° C. for 6 hours. Then, it cooled, the anionic unsaturated monomer and equimolar ammonia were added at 60 degreeC, and it stirred for 1 hour, and obtained the aqueous solution which contains 20% of polymers. It was 415 mPa · s of the copolymer.

Comparative Production Example 12
A reactor equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube in a 1 l four-necked flask is charged with 244 parts of deionized water and heated to 90 ° C. with stirring in a nitrogen gas atmosphere. Then, 15 parts of butyl acrylate, 70 parts of methacrylic acid, 60 parts of Aqualon HS1025 (Daiichi Kogyo Seiyaku Co., Ltd .: 25% by weight of polyoxyethylene nonylpropenyl phenyl ether ammonium sulfate), 2,4-diphenyl-4-methyl A mixture of 5 parts of -1-pentene is dropped over 2 hours. At the same time, a solution prepared by dissolving 2.5 parts of ammonium persulfate in 100 parts of deionized water as a polymerization initiator is added dropwise over 2 hours. Furthermore, after maintaining the temperature at 90 ° C. for 3 hours to complete the polymerization, 47 parts of 48% caustic soda was added to obtain a pale yellow turbid liquid containing 20% of the polymer. The viscosity of the copolymer was 175 mPa · s.

Comparative Production Example 13
In a 1 l 4-neck flask equipped with a stirrer, thermometer, nitrogen inlet tube and condenser, 50 parts of styrene, 10 parts of 2-ethylhexyl methacrylate, 40 parts of methacrylic acid, 5 parts of lauryl mercaptan, polyoxy 5 parts of sodium salt of ethylene (n = 13) dodecylphenyl ether sulfate, 2 parts of polyoxyethylene (n = 9) oleyl ether, 3 parts of potassium persulfate and 400 parts of water are mixed and polymerized at 80 ° C. for 4 hours. Went. Next, after cooling the reaction system to 50 ° C., an anionic monomer and an equimolar amount of ammonia were added to the system and stirred for 1 hour to prepare an aqueous solution containing 20% of a styrene-methacrylic acid copolymer neutralized product. Obtained. The viscosity of the copolymer was 70 mPa · s.

Comparative Production Example 14
Polymerization was conducted in the same manner as in Production Example 2 except that n-butyl methacrylate (50 parts), lauryl methacrylate (10 parts) and methacrylic acid (40 parts) were used as monomers instead of the monomers used in Production Example 6. The reaction was carried out to obtain an aqueous solution containing 20% of a copolymer neutralized product. The viscosity of the copolymer was 45 mPa · s.

[Production example of emulsion sizing agent (water dispersion) for papermaking]
Example 1
180 parts of the dehydration condensate obtained in Production Example 1 are heated and melted, and then mixed with 83.3 parts of the copolymer-based dispersant obtained in Production Example 6 and 403 parts of warm water (80 ° C.), and a high-pressure emulsifier is used. An emulsion sizing agent with a concentration of 30% was prepared by emulsifying with use. In addition, the average particle diameter was measured with a particle diameter measuring apparatus LASER DIFFRACTION PARTICLE SIZE ANALYZER SALD-2000J (manufactured by SHIMADZU) by laser diffraction / scattering method.

Examples 2-34, Comparative Examples 1-14
In Example 1, except that at least one of the obtained dehydration condensate and the dispersant was changed and the amount of the dispersant used was changed as shown in Table 2, the same procedure as in Example 1 was carried out. An emulsion sizing agent was prepared. The amount of the dispersant used corresponds to the weight percent of the dispersant solid content in the emulsion sizing agent solid content.

Comparative Example 15
180 parts of the dehydrated condensate obtained in Production Example 2 is heated and melted, then mixed with 8.9 parts of 48% caustic soda and 711 parts of hot water, and emulsified using a high-pressure emulsifier to give an emulsion size of 20%. An agent was prepared.

Comparative Example 16
180 parts of the dehydrated condensate obtained in Production Example 2 was heated and melted, and then mixed with 18 parts of Neugen ET109 (Daiichi Kogyo Seiyaku Co., Ltd .: polyoxyethylene oleyl cetyl ether) and 702 parts of hot water, and a high pressure emulsifier Was used to obtain an emulsion sizing agent having a concentration of 20%.

Hard emulsion dilution stability and sex mechanical stability of the emulsion sizing agents obtained in Examples 1 to 30 and Comparative Examples 1 to 14 were measured by the following methods. The results are shown in Table 2.

(1) Hard water dilution stability The emulsion sizing agent was diluted to 5% with hard water having a total hardness of 100 ° dH, and the dispersion state was observed. Evaluation was based on ◎: dispersed and stable for 1 day or longer, ○: dispersed, Δ: partially aggregated, x: aggregated.

(2) Mechanical stability 50 g of emulsion sizing agent was weighed into a container of a Marlon stability tester (manufactured by Shinsei Sangyo Co., Ltd.), temperature 25 ° C., load 10 kg, rotation speed 1000 r. p. m. After adding a mechanical shear for 5 minutes, the resulting aggregate was removed with a 350 mesh wire mesh, and the mechanical stability was calculated according to the following equation.

Mechanical stability (%) = (absolute dry weight of aggregate / absolute dry weight of sample emulsion sizing agent) × 100

(3) Internal size effect The paper size in the practical test (1), the practical test (2) and the practical test (3) using the emulsion sizing agents obtained in Examples 1 to 30 and Comparative Examples 1 to 14 The degree of sizing (seconds) of the resulting paper when used as an agent was measured according to the Steecht method (JIS P 8122) and Cobb water absorption (JIS P 8140, contact time with water 2 minutes). The total hardness was measured according to the chelate titration method of the total hardness measurement method (JIS K0101).

Practical test (1)
L-BKP was added with tap water in an amount of 2.0% to a pulp concentration, and beaten to 300 ml Canadian Standard Freeness using a beater. The beaten pulp slurry was further diluted with tap water to adjust the pulp concentration to 1.0%. A calcium chloride aqueous solution is added to this pulp slurry so that the total hardness is 15 ^o dH, and 16.0% (based on absolute dry weight) of filler (mixture of calcium carbonate and talc), 1.5% (absolutely dry). (Based on weight) sulfate band, commercially available cationized starch (Oji Ace K-100 manufactured by Oji Cornstarch Co., Ltd.) 0.3% (based on absolute dry weight), 0.2% of pulp as a sizing agent solid content (absolutely dry) After adding the emulsion type sizing agent prepared in the Examples and Comparative Examples so as to be based on weight, the papermaking was performed with a paper machine (Tappi Standard Sheet Machine (round shape)) so that the basis weight was 80 g / m ^2. did. The papermaking pH at this time was 7.9. The hand-wetted wet paper was dehydrated with a roll press machine under conditions of a linear pressure of 5.5 kg / cm and a feed rate of 2 m / min. The wet paper was dried at 80 ° C. for 150 seconds using a rotary dryer. The obtained test paper was conditioned for 24 hours in a constant temperature and humidity (23 ° C., 50% relative humidity) environment, and then measured for a Steecht sizing degree.
The results are shown in Table 3.

Practical test (2)
As the surface layer pulp, N-UKP / corrugated cardboard waste paper = 20% / 80% and 1.5% by weight pulp slurry was prepared. While stirring the slurry, an aqueous calcium chloride solution was added so that the total hardness would be 100 ^o dH, 200 ^o dH, and 300 ^o dH, respectively, and 1% sulfuric acid band (vs. pulp dry weight), polyacrylamide branched amphoteric paper Strength agent Polystron 1228 (manufactured by Arakawa Chemical Co., Ltd.) was added at 0.3%, and then emulsion type sizing agent (produced by Arakawa Chemical Industry Co., Ltd.) prepared at Examples and Comparative Examples was added at 0.2%. . Furthermore, as a back layer pulp, a pulp slurry was prepared with corrugated used paper, and 2% of a sulfuric acid band and 0.2% of a polyacrylamide branched amphoteric paper strength agent Polystron 1228 were added while stirring the slurry. Each of the pulp slurries treated with these additives was paper-made in accordance with JIS-P8222 to have a basis weight of 100 g / m ^2, and the pulp sheets were put together to obtain a wet paper sheet. The papermaking pH at this time was 6.8. The hand-wetted wet paper was dehydrated with a roll press machine under conditions of a linear pressure of 5.5 kg / cm and a feed rate of 2 m / min. The wet paper was dried at 80 ° C. for 150 seconds using a rotary dryer. The obtained test paper was conditioned for 24 hours in a constant temperature and humidity (23 ° C., 50% relative humidity) environment, and then the water absorption of the bumps (2 minutes) was measured. The results are shown in Table 3.

(4) Surface size effect practical test (3)
Commercially available oxidized starch (Oji Ace A made by Oji Cornstarch Co., Ltd.) was gelatinized at 90 ° C. with a solid content concentration of 15%, and using this, the oxidized starch was 5% in solid content concentration, in Examples and Comparative Examples. The prepared emulsion type surface sizing agent was contained at a solid content of 0.025%, and an aqueous calcium chloride solution was added so that the total hardness was 5 ^o dH to prepare a coating solution. The total hardness of the coating solution was 5 ^o dH. The obtained coating solution was applied to an uncoated neutral high-quality base paper (basis weight 80 g / m ² ) with a size press machine and dried by passing it through a rotary drum dryer at 110 ° C. for 1 minute (oxidation) The solid content adhesion of starch is 2.2 g / m ² , and the solid content adhesion of sizing agent is 0.011 g / m ² ). After drying, the humidity was adjusted for 24 hours under conditions of 23 ° C. and RH 50%, and then the degree of squeecht size of the obtained coated paper was measured. The results are shown in Table 3.

Claims (5)

A trivalent or tetravalent carboxylic acid (a1), a monovalent aliphatic alcohol (a2-1) having an alkyl group or alkenyl group having 6 to 22 carbon atoms, an alkyl group having 6 to 22 carbon atoms, and / or Or the dehydration condensate (A) and (meth) acrylamide (b1) obtained by dehydrating and condensing at least one compound (a2) selected from the group consisting of aliphatic amines (a2-2) having an alkenyl group 90 mol%, carboxyl group-containing monomer (b2) 2-40 mol%, sulfo group-containing monomer (b3) 0.1-10 mol%, and hydrophobic monomer (b4) 2 A papermaking emulsion sizing agent comprising a (meth) acrylamide copolymer (B) obtained by polymerizing a monomer containing 30 mol%. The (meth) acrylamide copolymer (B) is obtained by polymerizing a monomer further containing 0.1 to 5 mol% of the polyfunctional monomer (b5). Item 2. An emulsion sizing agent for papermaking according to Item 1. The emulsion sizing agent for papermaking according to claim 1 or 2, wherein the sulfo group-containing monomer (b3) is (meth) allylsulfonic acid and / or a salt thereof. The emulsion sizing agent for papermaking according to any one of claims 1 to 3, wherein the trivalent or tetravalent carboxylic acid (a1) is citric acid. The (meth) acrylamide copolymer (B) comprises (meth) acrylamide (b1) at 60 to 85 mol%, carboxyl group-containing monomer (b2) at 3 to 20 mol%, sulfo group-containing monomer ( b3) (meth) allylsulfonic acid and / or salt thereof is 0.5 to 5 mol%, and (meth) acrylic acid ester of alkyl alcohol having 1 to 12 carbon atoms as hydrophobic monomer (b4) is 5 to 5. The emulsion sizing agent for papermaking according to any one of claims 1 to 4, which is obtained by polymerizing a monomer containing 20 mol%.