JP2011047086A - Method for fixing sizing agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for fixing a sizing agent, by which a rosin-based sizing agent is improved in its fixation to express an excellent sizing effect, in the process of manufacturing paper or paperboards. <P>SOLUTION: In a feedstock prior to conducting a papermaking operation, a vinyl polymerization-based crosslinkable water-soluble cationic or amphoteric polymer of an electric charge inclusion rate of not less than 35 and not more than 90% is obtained by polymerization of a vinyl monomer or a vinyl monomer mixture, wherein the water-soluble cationic or amphoteric polymer is preferably a water-in-oil emulsion. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a sizing agent that improves sizing by adding a vinyl-polymerizable cross-linkable water-soluble cationic or amphoteric polymer having a charge inclusion rate of 35% or more and 90% or less to a papermaking raw material in a papermaking process. It is related with the fixing method.

In paper manufacturing in the paper industry, neutral papermaking has progressed, and the use of inexpensive calcium carbonate as a filler has become possible, resulting in advantages such as reduced manufacturing costs and higher quality products compared to acidic paper. It has been. In addition, paper making chemicals are also becoming more suitable with the neutral paper making. As for the sizing agent, an anionic acidic rosin-based sizing agent has been used in acidic papermaking, but in neutral papermaking, the addition rate of the sulfuric acid band that has been used as a fixing agent for rosin-based sizing agents has decreased, fixing. It was in a situation where the high size effect could not be manifested due to the decline in properties. For this reason, cationic sizing agents, alkenyl succinic anhydride sizing agents and alkyl ketene dimer sizing agents that have no dependence on sulfuric acid bands and have self-fixation to pulp fibers have been developed. However, since alkenyl succinic anhydride is easily hydrolyzed, it is necessary to emulsify at the papermaking site immediately before using the emulsifier and the fixing agent, and management is complicated. It has been pointed out that an alkyl ketene dimer sizing agent takes time to develop a size effect after papermaking is dried even if it is fixed on pulp fibers, or is inferior in suitability for electrophotography or ink jet printing. Like alkenyl succinic anhydride and alkyl ketene dimer sizing agents, rosin sizing agents are not cumbersome to manage and neutral rosin for neutral papermaking because of high sizing effect without inferior printing The use of size has come to be requested. Accordingly, various cationic water-soluble polymer fixing agents have been devised instead of the sulfuric acid band which has been conventionally used as a fixing agent for rosin sizing agents. For example, in Patent Document 1, a polymer containing 5 to 90 mol% of acryloyloxyethyltrimethylammonium salt as an essential component is proposed as a fixing agent. However, since the intrinsic viscosity is as high as 8 dl / g or higher, the paper product is high. There is concern that the condition of Furthermore, the surface charge of the pulp fibers is excessively neutralized, and the effect of the yield improver added downstream of the papermaking process is suppressed. As a result, the yield rate on the wire is reduced and the sizing agent is not fixed on the papermaking. The size effect is also poor. The use of a fixing agent (Patent Document 2) and a fixing agent (Patent Document 3) containing a cross-linking agent as a constituent component of polyacrylamide (PAM) -based polymers and having an intrinsic viscosity defined in consideration of the influence on the texture has been devised. However, the satisfactory fixing effect of the neutral rosin sizing agent has not been obtained yet. Therefore, in order to improve the sizing degree, it is necessary to increase the addition rate of the sizing agent, and the sizing agent that has not been fixed causes pitch troubles such as papermaking defects and dirt. There is a need for high size fixers.
JP-A-8-144189 JP 2002-249995 A Japanese Patent Laid-Open No. 2003-238631

An object of the present invention is to provide a fixing method for a rosin-based sizing agent for producing an excellent sizing effect in a paper and board making process.

As a result of intensive studies to solve the above problems, the charge inclusion rate obtained by polymerizing a vinyl monomer or a vinyl monomer mixture in a papermaking raw material before papermaking is 35% or more and 90% or less. It was discovered that the use of vinyl-polymerizable cross-linkable water-soluble cationic or amphoteric polymers can improve the fixability of rosin-based sizing agents in neutral papermaking and exhibit excellent size effects. The invention has been reached.

The present invention relates to a vinyl-polymerizable cross-linkable water-soluble cationic or amphoteric polymer having a charge inclusion rate of 35% or more and 90% or less obtained by polymerizing a vinyl monomer or a vinyl monomer mixture in a papermaking process. Is used. The vinyl polymer-based crosslinkable water-soluble cationic or amphoteric polymer is a monomer represented by the following general formula (1) and / or (2): A monomer mixture composed of 0 to 35 mol% of a monomer, 0 to 90 mol% of a copolymerizable nonionic water-soluble monomer, and a crosslinkable monomer is polymerized.




General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are alkyl groups having 1 to ₃ carbon atoms, alkoxy groups, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group, or a benzyl group. Different types may be used. A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.

General formula (2)
R ₅ represents hydrogen or a methyl group, R ₆ and R ₇ each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X ₂ represents an anion.

General formula (3)
R ₈ is hydrogen, methyl group or carboxymethyl group, Q is SO ₃ ⁻ , C ₆ H ₄ SO ₃ ⁻ , CONHC (CH ₃ ) ₂ CH ₂ SO ₃ ⁻ , C ₆ H ₄ COO ^— or COO ⁻ , R ₉ Represents hydrogen or COO ^— Y ₂ ⁺ , Y ₁ or Y ₂ represents hydrogen or a cation, respectively.

The feature of the present invention is that in the paper size fixing method, when a water-soluble polymer having a relatively high degree of crosslinking is used, the tendency of the molecular form to become more “particulate” in water becomes stronger, and the rosin-based sizing agent It was found that it was bonded to the surface of the particle at multiple points and fixed to the pulp fiber. By adding this water-soluble polymer, size fixing is improved as compared with a conventional rosin-based sizing agent, and an excellent sizing effect is exhibited.

The vinyl-polymerizable cross-linkable water-soluble cationic or amphoteric polymer of the present invention is a monomer used as a raw material, a cationic monomer, that is, a monomer represented by the general formula (1) and / or (2) 10 to 100 mol%, if necessary, an anionic monomer, that is, 0 to 35 mol% of a monomer represented by the general formula (3), a copolymerizable nonionic water-soluble monomer It can manufacture by polymerizing the monomer mixture which consists of 0-90 mol%, and the aqueous solution of a crosslinkable monomer. A particularly preferred form is a water-in-oil emulsion, in which the monomer aqueous solution is emulsified with a surfactant so that the water-immiscible organic liquid becomes a continuous phase and the monomer mixture aqueous solution becomes a dispersed phase. After polymerization, a phase inversion agent is added as appropriate.

In the vinyl polymerization crosslinkable water-soluble cationic or amphoteric polymer of the present invention, the monomer represented by the general formula (1) and / or (2) is 10 to 100 mol%, and the general formula (3). A monomer mixture composed of 0 to 35 mol% of a monomer, 0 to 90 mol% of a copolymerizable nonionic water-soluble monomer, and a crosslinkable monomer is polymerized. Preferably, the monomer represented by the general formula (1) and / or (2) is 20 to 95 mol%, the monomer represented by the general formula (3) is 0 to 35 mol%, and can be copolymerized. The nonionic water-soluble monomer is 5 to 80 mol%. This is because (meth) acrylamide or the like was copolymerized as a nonionic water-soluble monomer rather than 100 mol% of the monomer represented by the general formula (1) and / or (2). This is because the crosslinkable water-soluble polymer can be easily produced. Moreover, a crosslinkable monomer is 0.0005 to 0.01% by weight conversion with respect to all the monomers to be used, Preferably it is 0.001 to 0.005%.

Among the ionic monomers used in producing the vinyl polymerization crosslinkable water-soluble cationic or amphoteric polymer used in the present invention, the cationic monomers include the following examples. That is, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, methyl diallylamine and the like can be mentioned. Examples of the quaternary ammonium group-containing monomer include methyl chloride of the tertiary amino-containing monomer. (Meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy-2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxy, which are quaternized compounds by benzyl chloride Ethyldimethylbenzylammonium chloride, (meth) acryloyloxy-2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride, di A Lil dimethyl ammonium chlorides.

When the water-soluble amphoteric polymer is produced, a vinyl anionic monomer is used in combination with the vinyl cationic monomer. Examples thereof include vinyl sulfonic acid, vinyl benzene sulfonic acid or 2-acrylamido-2-methylpropane sulfonic acid, methacrylic acid, acrylic acid, itaconic acid, maleic acid, phthalic acid or p-carboxystyrene acid.

  Examples of the nonionic monomer used in producing the vinyl polymerization crosslinkable water-soluble cationic or amphoteric polymer of the present invention include (meth) acrylamide, N, N-dimethylacrylamide, acrylonitrile, (meth). Examples include 2-hydroxyethyl acrylate, diacetone acrylamide, N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, and acryloylmorpholine.

Specific examples of the crosslinkable monomer used in the present invention include divinyl compounds such as N, N′-methylenebisacrylamide and divinylbenzene, vinyl methylol compounds such as methylolacrylamide and methylolmethacrylamide, and vinyl aldehydes such as acrolein. Among them, the use of N, N′-methylenebisacrylamide is preferable.

The crosslinkable water-soluble cationic or amphoteric polymer used in the present invention has a charge encapsulation rate of 35% or more and 90% or less. The definition of the charge inclusion rate is also defined in Japanese Patent No. 4167969, that is, the definition 1 is shown below.
Definition 1) Charge inclusion ratio [%] for cationic cross-linkable water-soluble polymers and cross-linkable water-soluble polymers that are amphoteric and have a positive difference in the copolymerization rate between cationic monomers and anionic monomers ] = (1-α / β) × 100
α is a titration amount obtained by titrating a cross-linkable water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid with a potassium polyvinyl sulfonate aqueous solution. β is a titration obtained by adding a sufficient amount of neutralizing charge to a cross-linkable water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid, and then titrating with a polydiallyldimethylammonium chloride aqueous solution. Titration volume after subtracting blank value (blank value: titration volume of potassium polyvinylsulfonate aqueous solution titrated with polydiallyldimethylammonium chloride aqueous solution when no crosslinkable water-soluble polymer aqueous solution was added).
Definition 2) In the case of a crosslinkable water-soluble polymer that is amphoteric and has a negative difference in the copolymerization rate between a cationic monomer and an anionic monomer, the charge inclusion rate [%] = (1−α / β) × 100
α is a titration amount obtained by titrating a crosslinkable water-soluble polymer aqueous solution adjusted to pH 10.0 with ammonia with a polydiallyldimethylammonium chloride aqueous solution. β is a titration obtained by adding a sufficient amount of polydiallyldimethylammonium chloride aqueous solution to neutralize charge to a crosslinkable water-soluble polymer aqueous solution adjusted to pH 10.0 with ammonia, and then titrating with aqueous potassium vinyl sulfonate solution. A titration amount obtained by subtracting a blank value (blank value: titration amount obtained by titrating a polydiallyldimethylammonium chloride aqueous solution with a potassium polyvinylsulfonate aqueous solution when no 0.01% aqueous solution of a crosslinkable water-soluble polymer was added).

In the vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer of the present invention, the charge encapsulation rate is in the range of 35 to 90%.

Regarding the method of measuring the charge inclusion rate, a cationic cross-linkable water-soluble polymer and a cross-linkable water-soluble polymer that is amphoteric and has a positive difference in copolymerization rate between a cationic monomer and an anionic monomer Then, it is calculated as follows.
Charge inclusion rate [%] = (1−α / β) × 100
α represents a 0.01% aqueous solution of a crosslinkable water-soluble polymer adjusted to pH 4.0 with acetic acid using a Mutec PCD titrator (Mutek PCD-03, Mutek PCD-Two Titortor Version 2). This is a titration amount obtained by titration with an aqueous potassium sulfonate solution, dropping rate: 0.05 ml / 10 sec, and end point determination: 0 mV. β was added to a 0.01% aqueous solution of a crosslinkable water-soluble polymer adjusted to pH 4.0 with acetic acid in an amount sufficient to neutralize the charge with a 1 / 400N potassium polyvinyl sulfonate aqueous solution, and stirred sufficiently. Using a PCD titrator, titration is performed with a drop solution: 1 / 1000N polydiallyldimethylammonium chloride aqueous solution, drop rate: 0.05 ml / 10 sec, end point determination: 0 mV, and this titration value is subtracted from the blank value. The blank value means that a potassium polyvinyl sulfonate aqueous solution having the same concentration as that of the above sample adjusted to pH 4.0 with acetic acid is similarly added by a PCD titration apparatus using a dropping solution: 1 / 1000N polydiallyldimethylammonium chloride aqueous solution, dropping rate: 0.00. 05 ml / 10 sec, end point determination: titration at 0 mV.

For a crosslinkable water-soluble polymer that is amphoteric and has a negative difference in the copolymerization rate between the cationic monomer and the anionic monomer, the calculation is performed as follows.
Charge inclusion rate [%] = (1−α / β) × 100
α is a 0.01% aqueous solution of a crosslinkable water-soluble polymer adjusted to pH 10.0 with ammonia by a PCD titration apparatus (Mutek PCD-03, Mutek PCD-Two Titortor Version 2) manufactured by Mutech. This is a titration amount obtained by titration with a diallyldimethylammonium chloride aqueous solution, a dropping speed: 0.05 ml / 10 sec, and an end point determination: 0 mV. β is added to a 0.01% aqueous solution of a crosslinkable water-soluble polymer adjusted to pH 10.0 with ammonia, and a 1 / 400N polydiallyldimethylammonium chloride aqueous solution is added in an amount sufficient for charge neutralization, and is sufficiently stirred. Similarly, titrate with a PCD titrator at a dropping solution: 1 / 1000N potassium polyvinyl sulfonate aqueous solution, dropping rate: 0.05 ml / 10 sec, end point determination: 0 mV, and subtract this titration value from the blank value. The blank value is a polydiallyldimethylammonium chloride aqueous solution having the same concentration as that of the sample adjusted to pH 10.0 with ammonia in the same manner, using a PCD titrator, dropping solution: 1/1000 N potassium polyvinylsulfonate aqueous solution, dropping rate: 0.00. 05 ml / 10 sec, end point determination: titration at 0 mV.
The β value is considered to correspond to the theoretical charge calculated from the chemical composition of the crosslinkable water-soluble polymer. That is, since a large amount of opposite charges are present in the crosslinkable water-soluble polymer, it is considered that an electrostatic neutralization reaction is performed not only on the surface charges but also on the internal charges. If the degree of crosslinking is high, α is smaller than β, and the (1-α / β) value is larger than 1 and the charge inclusion rate is large (that is, the degree of crosslinking is high).

The vinyl polymerization crosslinkable water-soluble cationic or amphoteric polymer of the present invention is produced by copolymerizing a monomer mixture comprising an ionic monomer and a nonionic monomer and a crosslinkable monomer. be able to. Polymerization can be carried out by an ordinary polymerization method after preparing an aqueous solution in which these monomers are mixed.

As the polymerization method, after polymerization by aqueous solution polymerization, water-in-oil emulsion polymerization, water-in-oil dispersion polymerization, salt water dispersion polymerization, etc., it can be made into any product form such as aqueous solution, dispersion, emulsion or powder. . A preferred form is a water-in-oil emulsion polymerized product having a high concentration and a short dissolution time. Also preferred is a product obtained by drying and granulating the water-in-oil emulsion polymerized product without adding a phase inversion agent. This water-in-oil emulsion polymer can be produced by spray drying or directly drying and granulating with a dryer or the like.

As a method for producing a water-in-oil emulsion, a monomer mixture comprising an ionic monomer and a nonionic monomer and a crosslinkable monomer is water, and an oil comprising at least a water-immiscible hydrocarbon. This is a method of synthesizing by mixing a substance, an amount effective for forming a water-in-oil emulsion, and a surfactant having HLB, and stirring strongly to form a water-in-oil emulsion, followed by polymerization.

Examples of oily substances made of hydrocarbons used as a dispersion medium include paraffins, mineral oils such as kerosene, light oil, and medium oil, or hydrocarbons having characteristics such as boiling point and viscosity in substantially the same range as these. Synthetic oils or mixtures thereof may be mentioned. As content, it is the range of 20 weight%-50 weight% with respect to the total amount of water-in-oil emulsion, Preferably it is the range of 20 weight%-35 weight%.

Examples of surfactants having an HLB with an effective amount to form a water-in-oil emulsion are HLB 3-11 nonionic surfactants, specific examples of which are sorbitan monooleate, sorbitan monostearate Sorbitan monopalmitate, polyoxyethylene nonylphenyl ether, and the like. The amount of these surfactants to be added is 0.5 to 10% by weight, preferably 1 to 5% by weight, based on the total amount of the water-in-oil emulsion.

After the polymerization, a hydrophilic surfactant called a phase inversion agent is added to make the emulsion particles covered with the oil film easy to adjust to water, and the water-soluble polymer therein is easily dissolved. Dilute with and use for each application. Examples of hydrophilic surfactants are cationic surfactants and HLB 9-15 nonionic surfactants, such as polyoxyethylene polyoxypropylene alkyl ethers and polyoxyethylene alcohol ethers.

The polymerization conditions are usually appropriately determined depending on the monomer used and the copolymerization mol%, and the temperature is in the range of 0 to 100 ° C. In particular, when the water-in-oil emulsion polymerization method is applied, it is carried out in the range of 20 to 80 ° C, preferably 20 to 60 ° C. For the initiation of polymerization, a radical polymerization initiator is used. These initiators may be either oil-soluble or water-soluble, and can be polymerized by any of azo, peroxide, and redox systems. Examples of oil-soluble azo initiators are 2,2′-azobisisobutyronitrile, 1,1-azobiscyclohexanecarbonitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2 Examples include '-azobis-2-methylpropionate, 4,4'-azobis- (4-methoxy-2,4-dimethyl) valeronitrile.

Examples of water soluble azo initiators are 2,2'-azobis (amidinopropane) dichloride, 2,2'-azobis [2- (5-methyl-imidazolin-2-yl) propane] hydrogen dichloride And 4,4′-azobis (4-cyanovaleric acid). Examples of redox systems include a combination of ammonium peroxodisulfate and sodium sulfite, sodium hydrogen sulfite, trimethylamine, tetramethylethylenediamine and the like. Examples of peroxides include ammonium or potassium peroxodisulfate, hydrogen peroxide, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, succinic peroxide, t-butylperoxy-2-ethylhexanoate, etc. Can be mentioned.

The polymerization concentration of the monomer is in the range of 20 to 50% by weight, preferably in the range of 25 to 40% by weight. The concentration and temperature of the polymerization are appropriately determined depending on the monomer composition, the polymerization method, and the selection of the initiator. Set. The weight average molecular weight of the vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer obtained by polymerizing these monomers is preferably in the range of 100,000 to 6 million, more preferably in the range of 500,000 to 6 million. It is. If it exceeds 6 million, coarse flocs are formed, which adversely affects the texture and paper quality.

As a fixing method of the sizing agent in the present invention, not only the vinyl polymerization type crosslinkable water-soluble cationic or amphoteric polymer of the present invention but also other internal additive for papermaking can be added in combination. That is, fillers, paper strength agents, sulfuric acid bands, pitch control agents, dyes, yield improvers, drainage improvers, and the like can be used.

The water-soluble polymer having a charge encapsulation rate of 35% or more used in the present invention is in a state where crosslinking has progressed. When a high-molecular-weight linear water-soluble polymer is added, the aggregation flocs increase, but the resistance to shear is not large, and the coagulation action such as the adjustment of the surface charge is small. This is because the linear water-soluble polymer is present in a state where the molecules are spread in water. It is believed that the aggregating action of a high-molecular weight cationic water-soluble polymer such as a polymerization system is caused by a so-called “crosslinking adsorption action” of binding suspended particles by a molecular chain of the water-soluble polymer. However, the linear water-soluble polymer is in a stretched state, and the main function is to generate a large but fluffy aggregate floc produced by adsorbing suspended particles therein. Therefore, the function required for the fixing agent is hardly exhibited.

On the other hand, the crosslinkable water-soluble polymer suppresses the spread of molecules in water by crosslinking. Therefore, it exists as a more “dense packed” molecular form, and further cross-linking results in a water-insoluble and water-swellable gel. When the crosslinkable water-soluble polymer is added to the papermaking raw material, it adsorbs to the suspended particles and acts as an adhesive between the particles, resulting in aggregation of the particles. At this time, since it is a molecular form with “density”, it is considered that it binds to the surface of the rosin-based sizing agent particles at many points and is fixed to the pulp fiber. In particular, in the present invention, a water-soluble polymer having a relatively high degree of crosslinking is used. This water-soluble polymer having a relatively high degree of cross-linking has a strong tendency for a “density-packed” molecular form in water and a high “particulate” property. The high “particulate” nature increases the tendency to act like a coagulant like a sulfate band. The vinyl-polymerizable cross-linkable water-soluble cationic or amphoteric polymer used in the present invention has not only a cohesive action but also an aggregating action peculiar to the polymerized polymer, and the fixability of the rosin-based sizing agent is enhanced. In other words, the rosin sizing agent can be fixed due to the coagulation action, and at the same time, the action of agglomerating pulp fibers and fillers is increased. . If the charge encapsulation rate is higher than 90%, the crosslinking proceeds too much, and the amount of addition increases and the fixing ability to the sizing agent and pulp fibers decreases. The effect of the present invention is exhibited when the charge inclusion rate is 35% or more and 90% or less. However, depending on the properties of the papermaking raw material, if the charge inclusion rate is lower than 35%, the above effect is hardly exhibited and a high effect is obtained. It may not be possible. Therefore, a charge inclusion rate of 35% or more is preferable in order to cope with all papermaking raw materials.

  For neutral rosin sizes, the addition of a sulfuric acid band is essential, but by using the vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer of the present invention, the fixability is improved and the addition rate of the sulfuric acid band is reduced. can do. The sulfuric acid band is usually added in an amount of 1.5 to 2% per paper-making raw material, but can be reduced to 0.5 to 1.5%.

  The timing of adding the vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer of the present invention is preferably the same as that of the rosin sizing agent or after the addition of the rosin sizing agent. If it is added before the rosin sizing agent, it is not preferable because it is consumed by anionic impurities (anionic trash) and anionic papermaking chemicals in pulp fibers and papermaking raw materials.

The target papermaking raw material is not particularly limited, and can be applied to newsprint, high-quality paper, PPC paper, coated base paper, finely coated paper, paperboard and the like.

The following synthesis examples specifically illustrate the vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer of the present invention, but the present invention is not limited to the following synthesis examples.

(Synthesis Example 1)
A four-necked 500 ml separable flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube, 127.5 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C., 7.5 g of sorbitan monooleate and polyoxyethylene sorbitan monostearate 5 0.0 g was charged and dissolved. Separately, 18.4 g of deionized water, 101.3 g of 80 wt% acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 237.9 g of 50 wt% acrylamide (abbreviated as AAM), and 0.2% aqueous solution 2 of methylenebisacrylamide 0.0 g and 0.4 g of isopropyl alcohol (0.2% by weight of monomer) were collected and added. The oil and the aqueous solution were mixed and emulsified with stirring at 1000 rpm for 2 minutes with a homogenizer. The monomer composition at this time is DMQ / AAM = 20/80 (mol%).

After maintaining the temperature of the obtained emulsion monomer solution at 40 to 43 ° C. and performing nitrogen substitution for 30 minutes, 0.7 g of dimethyl-2,2-azobisisobutyrate (V-601, manufactured by Wako Pure Chemical Industries, Ltd.) (0.35% by weight of monomer) was added to initiate the polymerization reaction. The reaction was completed by polymerization at 42 ± 2 ° C. for 12 hours. After the polymerization, 10.0 g of polyoxyethylene decyl ether (2.0% by weight with respect to the liquid) was added to and mixed with the resulting water-in-oil emulsion as a phase inversion agent. When the product viscosity was measured with a B-type viscometer, it was 380 mPa · s. When the charge inclusion rate is determined by the colloid titration method and the above calculation formula, it is 35.5%, which is regarded as trial production-1. Further, by the same operation as in Synthesis Example 1, DMQ / AAM = 40/60 (mol%) charge inclusion rate 63.8% (prototype-2), DMQ / AAM = 70/30 (mol%) charge inclusion rate 52.3 % (Prototype-3), DMQ = 100 (mol%) charge inclusion rate 42.2% (prototype-4), DMQ / DMC / AAC / AAM = 20/10/5/65 (mol%) charge inclusion rate 76 Synthesis of a cross-linkable water-soluble polymer with 5% (prototype-5), DMQ / DMC / AAC / AAM = 60/10/10/20 (mol%) charge inclusion rate of 53.1% (prototype-6) did. The results are shown in Table 1.

  The water-in-oil emulsion liquid of Prototype-1 was collected on a metal test tray to a height of 5 mm, placed in a blower dryer, dried at 70 ° C. for 8 hours, crushed and crushed to form a powdery crosslink Water-soluble polymer was obtained. Prototype-7 (charge inclusion rate: 41.3%). Similarly, after trial manufacture-6 was dried, the lump was broken and pulverized to obtain a powdery crosslinkable water-soluble polymer. Prototype-8 (charge inclusion rate 55.0%).

(Comparative Synthesis Example 1)
A 4-neck 500 ml separable flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introduction tube was charged with 128.0 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C., 7.5 g of sorbitan monooleate and polyoxyethylene sorbitan monostearate 5 0.0 g was charged and dissolved. Separately, 19.9 g of deionized water, 101.3 g of 80% by weight acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 237.9 g of 50% by weight acrylamide (abbreviated as AAM), 0.4 g of isopropyl alcohol (per unit amount) Each 0.2% body weight) was collected and added. The oil and the aqueous solution were mixed and emulsified with stirring at 1000 rpm for 2 minutes with a homogenizer. The monomer composition at this time is DMQ / AAM = 20/80 (mol%).

The obtained emulsion was maintained at a temperature of the monomer solution at 40 to 43 ° C. and purged with nitrogen for 30 minutes, and then dimethyl-2,2-azobisisobutyrate (V-601, manufactured by Wako Pure Chemical Industries) 7 g (0.35% by weight of monomer) was added to initiate the polymerization reaction. The reaction was completed by polymerization at 42 ± 2 ° C. for 12 hours. After the polymerization, 10.0 g of polyoxyethylene decyl ether (2.0% by weight with respect to the liquid) was added to and mixed with the resulting water-in-oil emulsion as a phase inversion agent. Then, when the product viscosity was measured with a B-type viscometer, it was 410 mPa · s. When the charge inclusion rate is obtained by the above formula, it is 18.5%, which is set to trial production-9.
The results are shown in Table 1. Further, a crosslinkable water-soluble polymer having DMQ / AAM = 70/30 (mol%) and a charge inclusion rate of 95.0% was synthesized by the same operation as in Comparative Synthesis Example 1 (prototype-10). In addition, the water-in-oil emulsion liquid of Prototype-9 was collected on a metal test tray to a height of 5 mm, placed in a blast dryer and dried at 70 ° C. for 8 hours, and the mass was broken and crushed. Thus, a powdery cross-linkable water-soluble polymer was obtained. Prototype 11 (charge inclusion rate: 16.8%).

(Table 1)
DMQ: acryloyloxyethyltrimethylammonium chloride DMC: methacryloyloxyethyltrimethylammonium chloride, AAC: acrylic acid, AAM: acrylamide

Hardwood kraft pulp (LBKP) was beaten so that the value of Canadian Standard Freeness (CSF) was 400 mL, and the pulp slurry concentration was adjusted to 1% by weight. While collecting a predetermined amount of this pulp slurry and stirring at a stirring speed of 500 rpm, calcium carbonate (TP-121, manufactured by Okutama Kogyo) 10%, sulfuric acid band 1%, neutral rosin sizing agent (commercial product) 0.5% The fixing agent of the present invention, that is, vinyl polymerization crosslinkable water-soluble polymer samples -1 to 8 shown in Table 1 above, and 200 ppm (both for pulp slurry) were added at intervals of 10 seconds. After stirring for 2 seconds, 100 ppm of a yield improver (ND-200C, manufactured by Hymo) was added and stirred for 30 seconds. Thereafter, paper having a basis weight of 60 g / m ² was made using a TAPPI standard paper machine (using 60 mesh wire). The pH at the time of papermaking was 7.0. The paper wetting paper was press dehydrated with a press at 4.1 kgf / cm ² for 5 minutes, dried with a rotary drum dryer at 105 ° C. for 3 minutes, and then conditioned at 25 ° C. and RH 65% for 18 hours. The Steecht sizing degree (JISP8122) and the texture index were measured. The formation index is M / K System Inc. It measured by "3-D Sheet Analyzer" by a company. The higher this number, the better the texture. The results are shown in Table 2.

Using the same pulp slurry as in Example 1, the sizing agent addition rate was changed to 0.3% by the same operation, and the fixing agent of the present invention, that is, the vinyl polymerization crosslinkable water-soluble property shown in Table 1 above. Polymer samples-1, 3, 5 and 7 were added at 200 ppm (all with respect to pulp slurry), paper was made, and the Steecht sizing degree and texture index were measured. The results are shown in Table 2.

Using the same pulp slurry as in Example 1, the fixing agent of the present invention, that is, vinyl-polymerizable crosslinkable water-soluble polymer samples-1, 3, 5, and 7 shown in Table 1 above, was 100 ppm (any Was also added to pulp slurry), and papermaking was performed. The results are shown in Table 2.

(Comparative Example 1)
The same pulp slurry as in Example 1 was used, and the same operation was performed, that is, vinyl polymerized crosslinkable water-soluble polymer samples -9 to 11 shown in Table 1 and Comparative 1 (commercial product, polydimethyldiallylammonium chloride, weight). Papermaking was carried out under the conditions of adding or not adding 200 ppm (both for pulp slurry) with an average molecular weight of 500,000 and a charge inclusion rate of 5.7%, and the Steecht sizing degree and texture index were measured. The results are shown in Table 2.

(Table 2)

When the prototypes 1 to 8 of Example 1 were added, the Steecht sizing degree was improved as compared with the case where the prototypes 9 to 11 and Comparative 1 of the comparative example 1 were added. In addition, since the sizing human sizing degree was higher than that of Comparative Example 1 even under the conditions in which the sizing agent addition rate of Example 2 was reduced and the fixing agent addition rate of Example 3 was reduced, the drug addition rate was This leads to reduction in chemical costs due to the reduction and prevention of stains in the papermaking system by reducing the amount of sizing agent used. When the trial product-9 having strong linear properties of Comparative Example 1 is added, the formation index shows a large decrease compared to the non-addition of Comparative Example 1, but Examples 1 to 3 do not show a large decrease. The impact on the ground is considered low.

The cardboard waste paper was beaten so that the Canadian Standard Freeness (CSF) value was 290 mL, and the pulp slurry concentration was adjusted to 1% by weight. While collecting a predetermined amount of this pulp slurry and stirring at 500 rpm, the sulfuric acid band is 1.5%, the neutral rosin sizing agent (commercial product) is 0.5%, the fixing agent of the present invention, that is, in Table 1 above. Vinyl polymer crosslinkable water-soluble polymer samples -1 to 8 200 ppm (both for pulp slurry) are added at intervals of 10 seconds, and after adding the fixing agent, the mixture is stirred for 15 seconds, and then the freeness improver (FR-) is added. 740, made by Hymo) was added and stirred for 30 seconds. Thereafter, paper having a basis weight of 80 g / m ² was made using a TAPPI standard paper machine (using 60 mesh wire). The pH at the time of papermaking was 6.8. The wet paper we made is press dehydrated with a press at 4.1 kgf / cm ² for 5 minutes, dried with a rotary drum dryer at 105 ° C. for 3 minutes, and then conditioned for 18 hours at 25 ° C. and 65% humidity. The Steecht sizing degree and the texture index were measured. The results are shown in Table 3.

Using the same pulp slurry as in Example 4 and changing the addition rate of the sulfuric acid band to 1.0% by the same operation, the fixing agent of the present invention, that is, the vinyl polymerization crosslinkable water-soluble property shown in Table 1 above. Polymer samples-2, 4, 6 and 8 were added at 200 ppm (all with respect to pulp slurry), and the papermaking, the Steecht sizing degree and the texture index were measured. The results are shown in Table 3.

(Comparative Example 2)
The same pulp slurry as in Example 4 was used, and the same operation was performed, that is, 200 ppm (both for pulp slurry) of vinyl polymerized crosslinkable water-soluble polymer samples -9 to 11 and Comparative 1 shown in Table 1 were added or Papermaking was carried out under the additive-free conditions, and the Steecht sizing degree and the texture index were measured. The results are shown in Table 3.










(Table 3)

When the prototypes 1 to 8 of Example 4 were added, the Steecht sizing degree was improved as compared with Comparative Example 2. Even when the addition rate of the sulfuric acid band in Example 5 is decreased, the steecht degree is higher than that of the comparative example, and the sulfate band can be reduced. Improvement of fixing of rosin sizing agent by adding vinyl polymerization cross-linkable water-soluble polymer of the present invention means reduction of unfixed sizing agent in papermaking system, and suppression of troubles of papermaking defects and stains. It leads to. Moreover, compared with the additive-free texture index of Comparative Example 2, Examples 4 and 5 do not show a significant decrease, and the impact on texture is considered to be low.

  As described above, the fixing effect of the rosin sizing agent by the vinyl polymerized crosslinkable water-soluble polymer of the present invention was confirmed. This solves the problem of providing a fixing method that enhances fixing of the rosin sizing agent and exhibits an excellent size effect in the paper making process.

Claims (5)

A sizing agent fixing method characterized in that, in a papermaking step prior to papermaking, a paper is made by adding a vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer having a charge inclusion ratio of 35% or more and 90% or less to a papermaking raw material. . The vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer having a charge inclusion ratio of 35% or more and 90% or less is 10 to 100 mol% of a monomer represented by the following general formula (1) and / or (2) , A monomer mixture comprising 0 to 35 mol% of a monomer represented by the following general formula (3), 0 to 90 mol% of a copolymerizable nonionic water-soluble monomer, and a crosslinkable monomer The sizing agent fixing method according to claim 1, wherein the sizing agent is polymerized.
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are alkyl groups having 1 to ₃ carbon atoms, alkoxy groups, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group, or a benzyl group. Different types may be used. A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.

General formula (2)
R ₅ represents hydrogen or a methyl group, R ₆ and R ₇ each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X ₂ represents an anion.



General formula (3)
R ₈ is hydrogen, methyl group or carboxymethyl group, Q is SO ₃ ⁻ , C ₆ H ₄ SO ₃ ⁻ , CONHC (CH ₃ ) ₂ CH ₂ SO ₃ ⁻ , C ₆ H ₄ COO ^— or COO ⁻ , R ₉ Represents hydrogen or COO ^— Y ₂ ⁺ , Y ₁ or Y ₂ represents hydrogen or a cation, respectively. The form of the vinyl-polymerizable crosslinkable water-soluble cationic or amphoteric polymer is 10 to 100 mol% of the monomer represented by the general formula (1) and / or (2), and the general formula (3). A monomer mixture aqueous solution consisting of 0 to 35 mol% of the monomer represented, 0 to 90 mol% of the copolymerizable nonionic water-soluble monomer, and a crosslinkable monomer is A water-in-oil emulsion produced by emulsifying and polymerizing an immiscible organic liquid into a continuous phase and an aqueous monomer mixture solution as a dispersed phase, and then adding a phase inversion agent as appropriate. Item 3. A fixing method for a sizing agent according to Item 1 or 2. 4. The sizing agent fixing method according to claim 3, wherein the water-in-oil emulsion is dried and granulated without adding a phase inversion agent.   The sizing agent fixing method according to any one of claims 1 to 4, wherein the sizing agent is a neutral rosin sizing agent added to a papermaking raw material containing calcium carbonate as a filler.