JP2022182635A - Manufacturing method of size agent for papermaking - Google Patents

Abstract

To provide a manufacturing method of size agent for papermaking having more excellent size effect than conventional arts.SOLUTION: A manufacturing method of size agent for papermaking is characterized by that in the following steps (I) and/or (II), iodine and/or iodine compound used as a polymerizing component is used at the amount of 50 ppm or over as iodine atom per a monomer total amount. (I): a polymerizing step of a copolymer (A) containing a hydrophobic monomer (a1) and a hydrophilic monomer (a2) as a polymerizing component. (II): a polymerizing step of a hydrophobic monomer (b) in the presence of the copolymer (A) and/or a surfactant.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a method for producing a sizing agent for papermaking, and more particularly to a method for producing a sizing agent for papermaking that imparts excellent sizing performance by coating the surface of base paper.

Conventional papermaking sizing agents include quaternary styrene-dimethylaminoethyl (meth)acrylate copolymers and styrene-dimethylaminopropylacrylamide copolymers, which are dissolved resins consisting of hydrophobic and hydrophilic sites. Cationic solution type papermaking sizing agents such as quaternized products, alkali metal salts of styrene-maleic acid copolymers, alkali metal salts of styrene-(meth)acrylic acid copolymers, and α-olefin malein Anionic solution-type papermaking sizing agents such as alkali metal salts of acid copolymers are known. These solution-type sizing agents for papermaking have a high viscosity at a commercially available concentration, which makes it difficult to increase the concentration, resulting in cost problems. In addition, there is a drawback in that the sizing agent foams a lot, which tends to cause problems in the runnability during papermaking. Therefore, it is necessary to use a large amount of antifoaming agent together in order to improve the operability in an actual machine, which is unsatisfactory in terms of cost and size performance.

Emulsion types containing improved hydrophobic particles have recently become popular. By blending hydrophobic particles, it is possible to lower the viscosity of the product, and it is possible to reduce the cost and foamability by increasing the concentration, which was difficult with the solution type. These emulsion types include a cationic emulsion type and an anionic emulsion type. The cationic emulsion type is polymerized in the presence of epihalohydrin quaternized styrene-dimethylaminoalkyl (meth)acrylate copolymer. Internal sizing agents for papermaking produced by emulsion polymerization of a hydrophobic monomer, preferably styrene and 2-ethylhexyl acrylate (see, for example, Patent Document 1), and copolymers consisting of a styrenic compound and dialkylaminoalkyl (meth)acrylate. A surface sizing agent for papermaking produced by emulsion polymerization of a styrene compound and a (meth)acrylic acid ester having an alkyl group having 3 to 6 carbon atoms in the presence of a quaternized polymer (for example, see Patent Document 2), styrene For papermaking, a polymerizable hydrophobic monomer, preferably a styrenic compound, and a (meth)acrylic acid ester are emulsion polymerized in the presence of a quaternized product of a copolymer consisting of a dialkylaminoalkyl (meth)acrylamide. 100 parts by weight of a water-soluble copolymer containing a carboxyl group-containing unsaturated monomer and a hydrophobic unsaturated monomer as an anionic emulsion type surface sizing agent (see, for example, Patent Document 3). There is known a surface sizing agent for papermaking comprising an emulsion obtained by emulsion polymerization of 10 to 500 parts by weight of a hydrophobic unsaturated monomer in an aqueous solution containing the above (see, for example, Patent Document 4).

However, the size effect was not satisfactory.

JP-A-54-006902 JP-A-11-256496 JP-A-11-279983 JP-A-08-246391

The problem to be solved by the present invention is to provide a method for producing a papermaking sizing agent that is more excellent in sizing effect than conventional sizing agents.

The present inventors have made intensive studies to solve the above problems, and found that a sizing agent obtained by polymerization in the presence of iodine and/or an iodine compound has excellent sizing effects. completed.

That is, the present invention, which is a means for solving the above problems,
<1> Characterized by using 50 ppm or more of iodine and/or an iodine compound as iodine atoms with respect to the total amount of monomers used as polymerization components in the steps (I) and/or (II) below. A method for producing a papermaking sizing agent,
(I): Step of polymerizing a copolymer (A) containing a hydrophobic monomer (a1) and a hydrophilic monomer (a2) as polymerization components (II): Presence of a copolymer (A) and/or a surfactant Below, the step of polymerizing the hydrophobic monomer (b) <2> The mass ratio of the hydrophobic monomer (a1) and the hydrophilic monomer (a2) is hydrophobic monomer (a1):hydrophilic monomer (a2) = (50 ~85): The method for producing a papermaking sizing agent according to <1>, characterized in that (15 to 50);
<3> The mass ratio of the copolymer (A) and the hydrophobic monomer (b) is copolymer (A): hydrophobic monomer (b) = (10 to 100): (0 to 90) The method for producing the papermaking sizing agent according to <1> or <2>,
<4> The hydrophilic monomer (a2) of the copolymer (A) contains one or more selected from a vinyl monomer containing a tertiary amino group and a vinyl monomer containing a carboxylic acid group. The method for producing a papermaking sizing agent according to any one of <1> to <3> above,
is.

By using the papermaking sizing agent obtained by the method for producing a papermaking sizing agent of the present invention, it is possible to obtain paper excellent in sizing performance, and in particular, to improve the sizing performance of paperboard.

The present invention is obtained by using 50 ppm or more of iodine and/or an iodine compound as iodine atoms with respect to the total amount of monomers used as polymerization components in the steps (I) and/or (II) below. A method for producing a papermaking sizing agent.
(I): Step of polymerizing a copolymer (A) containing a hydrophobic monomer (a1) and a hydrophilic monomer (a2) as polymerization components (II): Presence of a copolymer (A) and/or a surfactant Below, the step of polymerizing the hydrophobic monomer (b)

According to the method for producing a papermaking sizing agent of the present invention, two types of papermaking sizing agents can be obtained, roughly classified as follows: (1) solution type and (2) emulsion type.

(1) Solution type A solution type papermaking sizing agent is obtained through the above step (I). Specifically, using a hydrophobic monomer (a1) and a hydrophilic monomer (a2) as polymerization components, polymerization is performed using a radical polymerization initiator in an appropriate solvent described later, and after the polymerization is completed, a solvent is optionally added. is a sizing agent for papermaking containing a copolymer (A) obtained by distilling off as a sizing agent component.

(2) Emulsion type The emulsion type papermaking sizing agent is obtained through the step (II) alone or through the steps (I) and (II). The sizing agent for papermaking contains, as a sizing agent component, hydrophobic particles obtained by emulsion polymerization of a hydrophobic monomer (b) as a polymerization component in the presence of a copolymer (A) and/or a surfactant. In this case, if the copolymer (A) is a copolymer containing a hydrophobic monomer (a1) and a hydrophilic monomer (a2) as polymerization components, it may be obtained in the step (I). , may be commercially available.

In the method for producing a papermaking sizing agent of the present invention, 50 ppm or more of iodine and/or iodine compounds are used as iodine atoms with respect to the total amount of monomers used as polymerization components in steps (I) and/or (II). do. In other words, the iodine and/or iodine compound may be used in at least one of the steps (I) and (II), and may be used in both steps (I) and (II). However, from the viewpoint of improving sizing properties compared to conventional papermaking sizing agents that do not use iodine and/or iodine compounds, the amount of iodine atoms should be 50 ppm or more relative to the total amount of monomers used in each step.

Examples of iodine and/or iodine compounds include iodine and iodine compounds such as iodoform, potassium iodide, and iodoacetic acid. Iodine and/or iodine compounds may be used alone or in combination of two or more.

The amount of iodine and/or iodine compound to be used can be appropriately determined according to the molecular weight of the polymer to be obtained. is preferred, more preferably 50 to 20000 ppm.

Examples of the hydrophobic monomer (a1) that can be used in step (I) include styrenes such as styrene, α-methylstyrene, vinyltoluene, and divinylbenzene; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth) acrylate, normal butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl ( Alkyl (meth)acrylates such as meth)acrylate, cyclohexyl (meth)acrylate and benzyl (meth)acrylate; dialkyl esters of maleic acid and fumaric acid; vinyl esters such as vinyl acetate and vinyl propionate; acrylonitrile and methacrylonitrile Nitriles such as; 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and other linear α-olefins; Cyclic olefins such as cyclohexene; N-alkyl (meth)acrylamides; Alkyl vinyl ethers such as methyl vinyl ether and these monomers can be used singly or in combination of two or more. Among these, styrenes and/or alkyl (meth)acrylates are preferred, and styrene and/or butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are more preferred.

Hydrophilic monomers (a2) that can be used in step (I) include cationic monomers, anionic monomers, and nonionic monomers. Among these, cationic monomers and anionic monomers are preferred. One or more of these hydrophilic monomers can be used.

The cationic monomer may be a vinyl monomer having cationic properties, specifically, primary amines such as allylamine; secondary amines such as diallylamine; dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate dialkylaminoalkyl (meth)acrylates such as; tertiary amines such as (dialkyl)aminoalkyl (meth)acrylamides such as dimethylaminopropyl (meth)acrylamide; Ammonium salts may be mentioned. One or more of these cationic monomers can be used.

A tertiary amine is preferably used as the cationic monomer because it can be expected to improve the stability and sizing performance of the sizing agent.

In the case of using the primary to tertiary amines, before or after the polymerization, neutralizing agents such as carboxylic acids such as formic acid and acetic acid, oxycarboxylic acids such as malic acid, tartaric acid and citric acid, as well as sulfuric acid and hydrochloric acid In order to impart hydrophilicity, it is preferable to form a salt using an inorganic acid such as.

Examples of anionic monomers include carboxyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid ester group-containing monomers, and salts thereof. One or more of these anionic monomers can be used. Anionic monomers are converted into salts by using alkalis such as alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, ammonia, and amine bases such as methylamine and dimethylamine as neutralizing agents before or after polymerization. is preferable because it can impart hydrophilicity.

Examples of carboxyl group-containing monomers include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, their acid anhydrides, neutralized salts, and half esters. Examples of containing monomers include vinylsulfonic acid, (meth)allylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, sulfonated styrene, and the like. Phosphate ester group-containing monomers include hydroxyalkyl (meth) ) phosphate esters of acrylates. Among these, carboxyl group-containing monomers are preferably used, and acrylic acid, methacrylic acid, maleic acid, and salts thereof are more preferred. One or more of these anionic monomers can be used.

Examples of nonionic monomers include (meth)acrylamide; hydroxyl group-containing (meth)acrylates such as hydroxyethyl acrylate and hydroxyethyl methacrylate. One or more of these nonionic monomers can be used.

The weight ratio of the hydrophobic monomer (a1) and the hydrophilic monomer (a2) is 50 to 85:15 to 50 for the hydrophobic monomer (a1):hydrophilic monomer (a2). It is preferable in terms of properties and sizing performance, and more preferably 70-85:15-30.

In addition, a copolymerizable vinyl monomer other than the hydrophobic monomer (a1) and the hydrophilic monomer (a2) may be used as a polymerization component of the copolymer (A) as long as it does not impair the effect of the papermaking sizing agent. good too. It is preferably less than 10% by mass of the polymer components constituting the copolymer (A).

Examples of radical polymerization initiators include oil-soluble azo initiators such as 2,2′-azobisisobutyronitrile and dimethyl 2,2′-azobis-(2-methylpropionate); oil-soluble organic peroxides such as libyl peroxybenzoate and tert-butyl peroxy-2-ethylhexanoate; persulfates such as ammonium persulfate, potassium persulfate and sodium persulfate; water-soluble such as hydrogen peroxide peroxides; redox polymerization initiators obtained by combining these persulfates and peroxides with reducing agents; water-soluble azo initiators such as 2,2′-azobis(2-amidinopropane) dihydrochloride; and Water-soluble organic peroxides such as tertiary butyl hydroperoxide can be used, but the present invention is not particularly limited to these, and other known and commonly used polymerization initiators can also be used. Two or more of these polymerization initiators may be used in combination.

The amount of polymerization initiator to be used is usually 0.5 to 10% by mass based on the total amount of monomers used in the present invention. Moreover, the polymerization initiator may be charged into the reaction vessel together with the monomer, or may be added dropwise continuously.

In addition, known chain transfer agents can be used, α-methylstyrene dimer; alkyl mercaptan compounds such as normal octyl mercaptan, tert-lead decyl mercaptan, normal dodecyl mercaptan; thioglycolic acid derivatives, mercaptopropionic acid derivatives, mercaptoethanol , thiomalic acid, and thiosalicylic acid; and alcohols such as ethanol and isopropyl alcohol.

These chain transfer agents may be charged together with the monomer into the reaction vessel, or may be added dropwise continuously. Two or more of these chain transfer agents may be used in combination. The amount of the chain transfer agent used depends on the chain transfer agent used, but is preferably in the range of 0 to 200% by mass with respect to the total amount of the monomers used in the present invention.

Solvents that can be used in step (I) include, for example, water; lower alcohol organic solvents such as methyl alcohol, ethyl alcohol and isopropyl alcohol; aromatic organic solvents such as benzene, toluene and xylene; acetone and methyl ethyl ketone. and acetic acid organic solvents such as acetic anhydride and glacial acetic acid, and these organic solvents can be used alone or in combination of two or more. Normally, after polymerization, water and, if necessary, an appropriate amount of neutralizing agent for copolymer (A) are mixed to form an aqueous solution. is preferred. Therefore, a lower alcohol-based solvent or a ketone-based organic solvent having a boiling point of less than 100° C., which can be easily distilled off after polymerization, and toluene, which can be distilled off azeotropically with water, are preferably used.

As the polymerization method in the step (I), for example, a batch addition polymerization method in which all the monomers are charged in a reaction vessel at once and polymerized, a divisional polymerization method in which a part or all of the monomers are dividedly added to the reaction vessel and polymerized An addition polymerization method, a continuous dropping polymerization method in which a part or all of the monomer is continuously dropped into a reaction vessel, and the like can be used.

The aqueous solution containing copolymer (A) obtained in step (I) can be used as it is as a solution-type papermaking sizing agent, but the aqueous solution can also be used in step (II).

When a cationic monomer having a tertiary amino group is used as the hydrophilic monomer (a2), it is preferable to quaternarize the tertiary amino group of the copolymer by a known and commonly used method. Examples of quaternizing agents that can be used for the quaternization include alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide, and oxides such as styrene oxide; methyl chloride, ethyl chloride, benzyl chloride, and epichlorohydrin. , glycidyltrimethylammonium chloride, and 3-chloro-2-hydroxypropyltrimethylammonium chloride; dimethyl sulfate, diethyl sulfate, and the like.

In the step (II), the hydrophobic monomer (b) is emulsion-polymerized in water in the presence of the copolymer (A) and/or a surfactant to form hydrophobic particles to form an emulsion.

The term "surfactant" as used in the present invention refers to known low-molecular-weight surfactants such as cationic, nonionic, amphoteric or anionic surfactants and radically polymerizable surfactants. At least one selected from the group can be used. The amount of surfactant used is generally 0 to 10% by mass relative to the total amount of monomers used in the present invention. In addition, the surfactant may be charged into the reaction vessel together with the monomer at once, or may be continuously added dropwise together with the monomer.

Examples of cationic surfactants include acetates and epichlorohydrin-modified primary and secondary amines, tetraalkylammonium chloride, trialkylbenzylammonium chloride, epichlorohydrin-modified rosinamine acetate, monooxy Ethylene alkylamine, polyoxyethylene alkylamine, and the like.

Examples of anionic surfactants include alkali salts of alkyl sulfates, alkyl ether sulfates, alkylbenzenesulfonates, and naphthalenesulfonic acid formalin condensates.

Examples of nonionic surfactants include polyoxyalkylene alkyl ethers, polyoxyalkylene alkylphenyl ethers, polyoxyalkylene fatty acid esters, sorbitan fatty acid esters, and the like.

Furthermore, radically polymerizable surfactants include, for example, (meth)allyl group, 1-propenyl group, 2-methyl-1-propenyl group, isopropenyl group, vinyl group, and (meth)acryloyl group in the molecule. Polyoxyalkylene alkyl ethers, polyoxyalkylene phenyl ethers, and polyoxyalkylene mono- or distyryl phenyl ethers having one or more functional groups with carbon-carbon double bonds, and sulfonates derived from these, sulfuric acid An ester salt etc. can be mentioned.

As the hydrophobic monomer (b), any of the monomers listed as the hydrophobic monomer (a1) used in step (I) can be used, and these monomers can be used singly or in combination of two or more. can do. Among these, styrenes and alkyl (meth)acrylates are preferable from the viewpoint of sizing performance and emulsion stability during emulsion polymerization, and styrene and/or butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are more preferable. preferable. Part of the hydrophobic monomer (b) may be replaced with a vinyl monomer copolymerizable with the hydrophobic monomer (b) as long as the effects of the present invention are not adversely affected.

When the copolymer (A) is used in step (II), the copolymer (A) and the hydrophobic monomer (b) have a mass ratio of (10 to 100):(0 to 90). , the stability of the resulting copolymer and sizing performance, and more preferably (20 to 100):(0 to 80).

In the step (II), the hydrophobic monomer (b) component is emulsion-polymerized in water using a radical polymerization initiator. law can be applied. . At this time, as the radical polymerization initiator, those that can be used in the step (I) can be similarly used.

Additives such as antioxidants, antifoaming agents, preservatives, chelating agents, and water-soluble aluminum compounds are added to the papermaking sizing agent obtained by the method for producing the papermaking sizing agent of the present invention, if necessary. can be

The papermaking sizing agent can be used as a papermaking surface sizing agent or as an internal sizing agent, but is preferably used as a surface sizing agent.

The surface sizing agent, when applied to the base paper, produces a sizing effect centered on the surface of the paper, while the internal sizing agent is added to the pulp slurry to produce the paper, resulting in a sizing effect on the entire paper. It is intended to produce an effect.

The pulp used for base paper or paper when used as a papermaking sizing agent includes bleached or unbleached chemical pulp such as kraft pulp or sulfite pulp, bleached or unbleached chemical pulp such as groundwood pulp, mechanical pulp or thermomechanical pulp. Unbleached high-yield pulp or waste paper pulp such as waste newsprint, waste magazine, waste cardboard or waste deinked paper can be used.

A water-soluble aluminum compound such as aluminum sulfate, a filler, a dye, an acidic papermaking rosin-based sizing agent, an alkylketene dimer-based and alkenylsuccinic anhydride-based neutral papermaking sizing agent, are added to a slurry obtained by dispersing the pulp in water. Additives such as sizing agents such as rosin-based sizing agents for neutral papermaking, dry strength agents, wet strength agents, retention aids, drainage improvers, coagulants, and antifoaming agents In order to develop the physical properties required for , it may be added as necessary to obtain base paper or paper, and when used as an internal sizing agent, it is added to the pulp slurry. Fillers include clay, talc, titanium oxide, and heavy and light calcium carbonate. These may be used alone or in combination.

Coating machines used as surface sizing agents include size presses, film presses, gate roll coaters, rod metering coaters, blade coaters, calendars, bar coaters, knife coaters, air knife coaters, and curtain coaters. can be done. Alternatively, the surface of the base paper can be coated with a spray coater.

When coating as a surface sizing agent, the sizing agent may be used as it is or diluted with water or the like. At least one selected from the group consisting of starches such as starch, celluloses such as carboxymethyl cellulose, polyvinyl alcohols, polyacrylamides, and water-soluble polymers such as sodium alginate is used by mixing with the coating solution. can also In addition, other surface sizing agents, pH adjusters such as aluminum sulfate, conductive agents such as sodium chloride and sodium sulfate, anti-slip agents, antiseptics, rust inhibitors, antifoaming agents, viscosity modifiers, dyes, pigments, etc. may be used together with additives.

Sized papers that can be obtained using papermaking sizing agents include various types of papers and paperboards. For example, recording paper such as PPC paper, inkjet recording paper, laser printer paper, form paper, thermal transfer paper, and thermal recording paper; coated paper such as art paper, cast coated paper, and high-quality coated paper; kraft paper, and pure white roll wrapping paper such as paper; western paper such as notebook paper and book paper; newsprint; paperboard for paper containers such as manila ball, white board and chipboard;

When applied as a surface sizing agent, the concentration of the coating solution is usually 0.1 to 5% by mass, preferably 0.2 to 1% by mass. If the amount is less than 0.1% by mass, the sizing effect may be insufficient, and if the amount is more than 5% by mass, the sizing effect is hardly improved and may be economically disadvantageous, which is preferable. do not have.

The coating amount is usually 0.01 to 1 g/m ² , preferably 0.02 to 0.2 g/m ² in terms of solid content. Within the above range, the size effect is exhibited particularly well.

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following description, "parts" and "%" mean parts by mass and % by mass, respectively, unless otherwise specified.

1-1. Production of papermaking sizing agent (cationic copolymer) (1) Production of solution type (Example 1)
75 parts of styrene as the hydrophobic monomer (a1), 25 parts of dimethylaminoethyl methacrylate as the hydrophilic monomer (a2), and 1.0 parts of iodine as an iodine compound (10,000 ppm relative to the monomer as iodine atoms), 2.0 parts of azobisisobutyronitrile, and 50 parts of toluene were charged, maintained at 80° C. for 7 hours, and then azobisisobutyronitrile. 0.7 part of was added and the temperature was maintained for 3 hours. After adding 10.6 parts of 90% acetic acid as a neutralizing agent, 200 parts of water was added to obtain an emulsion, and the temperature was further raised to distill off toluene.
Next, 14.7 parts of epichlorohydrin (100 mol % with respect to dimethylaminoethyl methacrylate) is added as a quaternizing agent, reacted at 60° C. for 4 hours, and 258 parts of water is added to obtain a copolymer (A- A solution type papermaking sizing agent containing 20.1% of 1) as a solid content was obtained.

(Comparative example 1)
A solution-type comparative papermaking sizing agent containing copolymer (A-2) was obtained in the same manner as in Example 1, except that iodine and/or an iodine compound was not used.

(Comparative example 2)
A solution containing the copolymer (A-2) obtained in Comparative Example 1 was neutralized with iodine dissolved in isopropyl alcohol, and 10000 ppm was added to the copolymer mass before quaternization. A solution-type comparative papermaking sizing agent was obtained as a solution containing (A-3).

(Explanation of abbreviations in the table)
St: styrene DMEM: dimethylaminoethyl methacrylate Epi: epichlorohydrin

*Added after polymerization to the solution containing the copolymer (A-2).

(2) Production of emulsion type (Example 2)
Into the same reactor as in Example 1, 500 parts of the aqueous solution of the copolymer (A-1) produced in Example 1 (100 parts as solid content) was added, 192 parts of water, and isobutyl methane as the hydrophobic monomer (b). 50 parts of acrylate and 50 parts of normal butyl acrylate, 0.10 parts of iodine as an iodine compound (as an iodine atom, 1000 ppm relative to the monomer) and 5% 2,2'-azobis (2-methylpropiondiamidine) dihydrochloride (Fujifilm Wako Pure Chemical Industries, Ltd.: water-soluble azo polymerization initiator V-50) aqueous solution (hereinafter sometimes abbreviated simply as "5% V-50 aqueous solution") was added, and 10 parts by weight were added and mixed and stirred under a nitrogen stream. The temperature was raised to 80° C. while The emulsion polymerization reaction was completed by holding at 80° C. for 4 hours to obtain an emulsion type papermaking sizing agent (E-1) having a solid concentration of 25%.

(Examples 3-16, Comparative Examples 3-4)
Table 2 shows the type and amount of hydrophobic monomer (a1) used, the type and amount of hydrophilic monomer (a2), the amount of quaternizing agent, and the type and amount of iodine and/or iodine compound used. Solutions containing copolymers (A-4) to (A-9) were obtained in the same manner as in Example 1 except that It was used when polymerizing the sizing agent.
Next, the type and amount of copolymer (A) used, the type and amount of hydrophobic monomer (b) used, and the type and amount of iodine and/or iodine compound used were changed as shown in Table 3. Emulsion type papermaking sizing agents (E-2) to (E-17) were obtained in the same manner as above.

(Explanation of abbreviations, etc. in the table)
St: styrene IBMA: isobutyl methacrylate TBA: t-butyl acrylate DMEM: dimethylaminoethyl methacrylate DMPMA: dimethylaminopropyl methacrylamide Epi: epichlorohydrin

*As an iodine atom

(Explanation of abbreviations in the table)
IBMA: isobutyl methacrylate BA: n-butyl acrylate St: styrene EHA: 2-ethylhexyl acrylate

*As an iodine atom

1-2. Evaluation test of sizing agent for papermaking as surface sizing agent (Test Example 1) Evaluation of sizing performance in paperboard (1) Papermaking of paperboard base paper 380ml Canadian standard freeness, ash content 10.0%, pH 7.0 Corrugated waste paper Using pulp, aluminum sulfate is 1.0% based on the pulp (absolute dry mass basis), PAM-based paper strength agent (manufactured by Seiko PMC Co., Ltd.; DS4433) is 0.3% as a paper strength agent, and rosin-based size is used as a sizing agent. A 0.1% agent (CC1401 manufactured by Seiko PMC Co., Ltd.) was sequentially added and diluted to 0.8% with water having an electrical conductivity of 170 mS/m. After that, 0.01% (on an absolute dry mass basis) of a retention aid (Hymo Lock ND300, manufactured by Hymo Co.) was added to the diluted pulp slurry, and the basis weight was adjusted to 120 g/m ² by a Noble & Wood paper machine. Paper was made. The papermaking pH at this time was 7.3. The wet paper was dried using a drum dryer under conditions of 100° C. for 160 seconds.

(2) Method for preparing coating liquid Corn starch (Corn Starch Y, manufactured by Nihon Shokuhin Kako Co., Ltd.) is diluted with water to a concentration of 10%, and 1% ammonium persulfate is added to the solid content of starch to obtain 95%. ℃ for 20 minutes, adjusted to pH 6.0 with sodium hydroxide, and then the papermaking sizing agents obtained in Examples 1 to 16 and Comparative Examples 1 to 4 were adjusted to the following solid content concentrations. A coating solution was prepared by adding as follows.
Solid content concentration of coating solution: Ammonium persulfate-modified starch: 6%, papermaking sizing agent: 0.3%

(3) Production of paperboard and evaluation of sizing performance The coating solution blended in (2) above was applied to the base paper produced in (1) above using a size press. The solid content coating amount of the surface sizing agent of this coated paper was 0.06 g/m ² . After coating, drying was performed at 100° C. for 80 seconds using a drum dryer. The obtained test paper was conditioned for 24 hours in a constant temperature and humidity (23° C., 50% relative humidity) environment, and the Cobb water absorbency (120 seconds) (according to JISP8140) was measured. The smaller the Cobb water absorption value, the better the sizing performance. Table 4 shows the evaluation results.

The papers of Evaluation Examples 1 to 16 in Table 4 produced using the papermaking sizing agent of the present invention are the papers of Comparative Evaluation Examples 1 to 4 produced using papermaking sizing agents different from the papermaking sizing agent of the present invention. From the evaluation results, it can be seen that the sizing performance (cobb water absorbency) is superior to that of paper.

2-1. Production of papermaking sizing agent (anionic copolymer) (1) Production of solution type (Example 17)
In the same reactor as in Example 1, 70 parts of styrene as a hydrophobic monomer (a1), 30 parts of methacrylic acid as a hydrophilic monomer (a2), and 1.2 parts of iodine as an iodine compound (as iodine atoms, 12000 ppm relative to the monomer) , 2.0 parts of azobisisobutyronitrile and 100 parts of isopropyl alcohol were charged and maintained at 80° C. for 7 hours, then 1.0 part of azobisisobutyronitrile was added and further maintained at the same temperature for 3 hours. After adding 65.2 parts of 30% potassium hydroxide as a neutralizing agent, 300 parts of water was added, and the temperature was further raised to distill off the isopropyl alcohol. Water was added to obtain a solution type papermaking sizing agent containing 20.2% of the copolymer (A-10) as a solid content.

(Comparative Example 5)
A solution-type comparative papermaking sizing agent containing copolymer (A-11) was obtained in the same manner as in Example 17, except that iodine was not used.

(Comparative Example 6)
Copolymer (A-12 ) was obtained as a solution type comparative papermaking sizing agent.

(Explanation of abbreviations in the table)
St: Styrene MAA: Methacrylic acid KOH: Potassium hydroxide

*Added after polymerization to the solution containing the copolymer (A-11).

(2) Production of emulsion type (Examples 18-32, Comparative Examples 7-8)
Examples except that the type and amount of the hydrophobic monomer (a1) used, the type and amount of the hydrophilic monomer (a2), and the type and amount of iodine and/or iodine compound used were changed as shown in Table 6. Solutions containing copolymers (A-13) to (A-18) were obtained in the same manner as in No. 17, and used in polymerizing the sizing agents of Examples 21 to 24, 28 and 29. did.
Next, the type and amount of copolymer (A) used, the type and amount of hydrophobic monomer (b) used, and the type and amount of iodine and/or iodine compound used were changed as shown in Table 7, and 5% V Emulsion type papermaking sizing agents (E-18) to (E-34) were obtained in the same manner as in Example 2, except that the -50 aqueous solution was changed to 5% ammonium persulfate.

(Explanation of abbreviations, etc. in the table)
St: styrene IBMA: isobutyl methacrylate EHA: 2-ethylhexyl acrylate MAA: methacrylic acid MAn: maleic anhydride AA: acrylic acid IA: itaconic acid KOH: potassium hydroxide

*As an iodine atom

(Explanation of abbreviations, etc. in the table)
IBMA: isobutyl methacrylate BA: n-butyl acrylate St: styrene EHA: 2-ethylhexyl acrylate

*As an iodine atom

2-2. Evaluation test of papermaking sizing agent as surface sizing agent (Test Example 2) Evaluation of sizing performance in neutral high-quality paper (1) Production of base paper for neutral high-quality paper
380 ml of pulp beaten to Canadian Standard Freeness (mixed pulp with a hardwood to softwood pulp ratio of 9 to 1) was made into a 2.5% slurry, and calcium carbonate was added to the pulp at a ratio of 2% (bone dry weight basis). (TP121S manufactured by Okutama Industry Co., Ltd.) was added. Next, 0.5% of the pulp (bone dry weight basis) aluminum sulfate, 0.5% of the pulp (bone dry weight basis) cationized starch (manufactured by National Starch; Cato 304) and 0.03% of the pulp ( Bone dry weight basis) of alkyl ketene dimer sizing agent (manufactured by Seiko PMC Co., Ltd.; AD1602) was sequentially added, and then this pulp slurry was diluted with dilution water of pH 7.5 to a concentration of 0.25%. After that, the diluted pulp slurry was added with calcium carbonate (TP121S, manufactured by Okutama Kogyo Co., Ltd.) of 15% (on an absolute dry weight basis) and a yield improver (manufactured by Hymo Co., Ltd.) on a 0.01% basis (on an absolute dry weight basis) of the pulp. NR12MLS) was added, and paper was made to a basis weight of 65 g/m ² with a Noble and Wood paper machine. The papermaking pH at this time was 7.5. Drying of the wet paper was performed using a drum dryer at 100° C. for 80 seconds.

(2) Method for preparing coating liquid Oxidized starch (MS3800, manufactured by Nihon Shokuhin Kako Co., Ltd.) was diluted with water to a concentration of 10%, gelatinized at 95 ° C. for 20 minutes, and then Examples 17 to 32 and Comparative Examples. A coating solution was prepared by adding the sizing agent for papermaking and sodium chloride (NaCl) obtained in 5 to 8 so that the solid content concentration would be as follows.
Solid content concentration of coating solution: Oxidized starch...6%, papermaking sizing agent...0.3%, NaCl...0.5%

(3) Production of neutral fine paper and evaluation of sizing performance The coating solution blended in (2) above was applied to the base paper made in (1) above using a size press to obtain neutral fine paper. . The solid content coating amount of the papermaking sizing agent for this coated paper was 0.05 g/m ² . After coating, drying was performed at 100° C. for 80 seconds using a drum dryer. The resulting test paper was conditioned in a constant temperature and humidity (23° C., 50% relative humidity) environment for 24 hours, and the Stockigt sizing degree was measured according to JIS P8122. A larger Stockigt sizing degree value means better sizing performance. Table 8 shows the results.

The papers of Evaluation Examples 17 to 32 in Table 8 produced using the papermaking sizing agent of the present invention are the papers of Comparative Evaluation Examples 5 to 8 produced using papermaking sizing agents different from the papermaking sizing agent of the present invention. The evaluation results show that the sizing performance (Steckigt sizing degree) is superior to that of paper.

3-1. Production of papermaking sizing agent (emulsion type using surfactant) (Example 33)
In the same reactor as in Example 1, 10 parts of Lipocard T-30 (surfactant manufactured by Lion Corporation, stearyltrimethylammonium chloride) as a surfactant (3 parts as solid content), 292 parts of water, hydrophobic 50 parts of isobutyl methacrylate and 50 parts of normal butyl acrylate as the monomer (b), 0.10 parts of iodine as an iodine compound (1000 ppm as iodine atom relative to the monomer) and 10 parts by weight of a 5% V-50 aqueous solution were added and mixed under a nitrogen stream. The temperature was raised to 80° C. while mixing and stirring at . The emulsion polymerization reaction was completed by holding at 80° C. for 4 hours to obtain an emulsion type papermaking sizing agent (E-35) having a solid concentration of 25%.

(Example 34, Comparative Examples 9 and 10)
Next, the type of surfactant and the amount of iodine and/or iodine compound used were changed as shown in Table 9, and emulsion type papermaking sizing agents (E-36) to (E- 38) was obtained.

(Explanation of abbreviations, etc. in the table)
T-30: Lipocard T-30 (Lion Corporation surfactant, stearyltrimethylammonium chloride)
N210: Newcoal 210 (Surfactant manufactured by Nippon Nyukazai Co., Ltd., alkylbenzene sulfonate)
IBMA: isobutyl methacrylate BA: n-butyl acrylate

*As an iodine atom

3-2. Evaluation test of papermaking sizing agent as surface sizing agent (Test Example 3) Evaluation of sizing performance in neutral high-quality paper (1) Production of base paper for neutral high-quality paper
380 ml of pulp beaten to Canadian Standard Freeness (mixed pulp with a hardwood to softwood pulp ratio of 9 to 1) was made into a 2.5% slurry, and calcium carbonate was added to the pulp at a ratio of 2% (bone dry weight basis). (TP121S manufactured by Okutama Industry Co., Ltd.) was added. Next, 0.5% of the pulp (bone dry weight basis) aluminum sulfate, 0.8% of the pulp (bone dry weight basis) cationized starch (manufactured by National Starch; Cato 304) and 0.03% of the pulp ( Bone dry weight basis) of alkyl ketene dimer-based sizing agent (manufactured by Seiko PMC Co., Ltd.; AD1638) was sequentially added, and then this pulp slurry was diluted with dilution water of pH 7.5 to a concentration of 0.25%. After that, the diluted pulp slurry was added with calcium carbonate (manufactured by Okutama Kogyo Co., Ltd.; TP121S) at a ratio of 15% (on an absolute dry weight basis) to the pulp, and a PAM-based paper strength agent (Seiko PMC) at a ratio of 0.1% (on an absolute dry weight basis) to the pulp. ^Co. , Ltd.; The papermaking pH at this time was 7.5. Drying of the wet paper was performed using a drum dryer at 100° C. for 80 seconds.

(2) Method for preparing coating liquid Tapioca starch (MKK-100, manufactured by Matsutani Chemical Industry Co., Ltd.) is diluted with water to a concentration of 10%, and 0.1% Kleistase E5CC ( Amano Enzyme Co., Ltd.) was added to prepare an enzyme-modified starch, which was gelatinized at 95° C. for 20 minutes. Thereafter, the papermaking sizing agents obtained in Examples 33 and 34 and Comparative Examples 9 and 10 were added so as to have the following solid content concentrations to prepare coating solutions.
Solid content concentration of coating liquid: enzyme-modified starch...7%, sizing agent for papermaking...0.5%

(3) Production of neutral fine paper and evaluation of sizing performance The coating solution blended in (2) above was applied to the base paper made in (1) above using a size press to obtain neutral fine paper. . The solid content coating amount of the papermaking sizing agent for this coated paper was 0.08 g/m ² . After coating, drying was performed at 100° C. for 80 seconds using a drum dryer. The resulting test paper was conditioned in a constant temperature and humidity (23° C., 50% relative humidity) environment for 24 hours, and the Stockigt sizing degree was measured according to JIS P8122. Table 10 shows the results.

The papers of Evaluation Examples 33 and 34 in Table 10 produced using the papermaking sizing agent of the present invention are the papers of Comparative Evaluation Examples 9 and 10 produced using papermaking sizing agents different from the papermaking sizing agent of the present invention. The evaluation results show that the sizing performance (Steckigt sizing degree) is superior to that of paper.

Claims (4)

A papermaking size obtained by using 50 ppm or more of iodine and/or an iodine compound as iodine atoms with respect to the total amount of monomers used as polymerization components in the following steps (I) and/or (II). A method for producing the agent.
(I): Step of polymerizing a copolymer (A) containing a hydrophobic monomer (a1) and a hydrophilic monomer (a2) as polymerization components (II): Presence of a copolymer (A) and/or a surfactant Below, the step of polymerizing the hydrophobic monomer (b) The mass ratio of the hydrophobic monomer (a1) and the hydrophilic monomer (a2) is hydrophobic monomer (a1):hydrophilic monomer (a2)=(50-85):(15-50). A method for producing the papermaking sizing agent according to claim 1 . The mass ratio of the copolymer (A) and the hydrophobic monomer (b) is copolymer (A): hydrophobic monomer (b) = (10 to 100): (0 to 90). The method for producing the papermaking sizing agent according to claim 1 or 2. A claim characterized in that the hydrophilic monomer (a2) of the copolymer (A) contains one or more selected from a vinyl monomer containing a tertiary amino group and a vinyl monomer containing a carboxylic acid group. A method for producing the papermaking sizing agent according to any one of 1 to 3.