JP2011012354A - Freeness-improving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freeness-improving method by which the yield rate on a wire part is improved and the freeness, water drainage, and productivity are improved in a process for making paper or cardboard.SOLUTION: The freeness-improving method includes applying a vinylic polymer-based cross-linkable water-soluble cationic or amphoteric polymer obtained by emulsion-polymerization of a vinylic monomer or a vinylic monomer mixture and having a charge intensive rate of 15 to 90% to a paper-making raw material before forming paper.

Description

In the papermaking process of the paperboard, by adding a vinyl polymerization cross-linkable water-soluble cationic or amphoteric polymer having a charge inclusion rate of 15% or more and 90% or less, the drainage and water squeezing are improved and the productivity is improved. The present invention relates to a method for improving drainage.

In paper manufacturing, especially in the papermaking process for paperboards such as liners and core base paper, there is a strong demand for improved drainage in the wire part and improved drying in the dryer part from the viewpoint of improving production efficiency by increasing the papermaking speed. . In recent years, the proportion of waste paper is increasing from the viewpoint of resource saving and energy saving, and the proportion of impurities and fine fibers in the papermaking raw material that are accumulated in circulation is increasing. Therefore, in order to improve the drainage on a wire and the squeezing in a press part, the more effective drainage improvement prescription is requested | required. Conventionally used formulations for improving drainage include a formulation using polyethyleneimine. However, since a large amount of addition is necessary, there are disadvantages such as high addition cost and foaming of water. For this reason, an improved invention of polyethyleneimine and a prescription (Patent Document 1) using polyethyleneimine have been proposed, but no significant improvement in drainage and squeezing has been achieved. In addition, polyacrylamide-based cationic polymer may be used, but since the yield improvement of the papermaking raw material with wire is mostly a linear high molecular weight type of main use, the yield rate is improved, There are cases where excessive moisture is taken into the floc formed by the polymer and the drainage and squeezability are lowered. Therefore, it is necessary to adjust the cation density and molecular weight of the polymer in order to increase drainage and squeezing, but it is difficult to satisfy both the yield and drainage effect according to the properties of the papermaking material. is there. Various formulations have also been proposed in which the acrylamide polymer has a branched structure to improve drainage (Patent Document 2), but these have mainly a function as a paper strength enhancer, so that the molecular weight is insufficient. In particular, there is no significant improvement in drainage for papermaking raw materials containing waste paper and containing a large amount of fine fibers, and there is little mention of improvement in water squeezing in the press part and dryer part. In addition, there is no prior literature describing the degree of crosslinking and water squeezing with respect to the drainage formulations proposed so far.
JP 2001-295193 A JP 2000-239326 A

This invention makes it a subject to provide the drainage improvement method which improves the yield rate in a wire in the paper-making process of paperboard, and aims at the improvement of drainage, squeezing, and productivity.

As a result of intensive studies to solve the above problems, the charge inclusion rate obtained by emulsion polymerization of a vinyl monomer or a vinyl monomer mixture in a papermaking raw material before papermaking is 15% or more and 90% or less. It is possible to improve the yield of papermaking raw materials on the wire, improve drainage and squeezing, and improve productivity by using a vinyl-polymerizable crosslinkable water-soluble cationic or amphoteric polymer. The present invention has been discovered.

The present invention relates to a vinyl polymerization crosslinkable water-soluble cationic or amphoteric heavy polymer having a charge inclusion rate of 15% or more and 90% or less obtained by emulsion polymerization of a vinyl monomer or a vinyl monomer mixture in a papermaking process. Use coalescing. 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)
R1 is hydrogen or a methyl group, R2 and R3 are alkyl groups having 1 to 3 carbon atoms and alkoxy groups, and R4 is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and may be the same or different. A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X1 represents an anion.


General formula (2)
R5 represents hydrogen or a methyl group, R6 and R7 each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X2 represents an anion.

General formula (3)
R8 is hydrogen, methyl or carboxymethyl ^{group, Q} represents ^{SO3 -, C6H4SO3 -, CONHC (} CH3) 2CH2SO3 -, C6H4COO - or ^COO -, R9 is hydrogen or ^COO - ^Y2 +, Y1 or Y2 is hydrogen or a cation Represent each.

The feature of the present invention resides in the discovery of a drug capable of improving the drainage and the squeezability in the method for improving the drainage of paperboard while maintaining a high yield rate as compared with the conventional drainage improver. By adding this agent, a high yield is maintained, and the effect of improving the drainage with a wire or the pressability with a press part 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.

Among the ionic monomers used in producing the vinyl polymerization crosslinkable water-soluble cationic or amphoteric polymer of the present invention, cationic monomers, that is, represented by the general formulas (1) and / or (2) The monomer to be used is 10 to 100 mol%, preferably 15 to 90 mol%.

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 15% 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 rate in the case of 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 crosslinkable 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) Charge inclusion rate [%] = (1-α / β) × 100 in the case of a cross-linkable water-soluble polymer that is amphoteric and has a negative difference in copolymerization rate between a cationic monomer and an anionic monomer
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 potassium vinyl sulfonate aqueous solution. Titration amount after subtracting blank value (blank value: titration amount obtained by titrating an aqueous polydiallyldimethylammonium chloride solution with an aqueous potassium polyvinyl sulfonate solution when no 0.01% aqueous solution of a crosslinkable water-soluble polymer was added).

The vinyl polymerization type cross-linkable water-soluble cationic or amphoteric polymer of the present invention has a charge inclusion ratio in the range of 15% to 90%, preferably in the range of 35 to 90%.

Regarding the method for 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 the copolymerization rate between a cationic monomer and an anionic monomer Then, it is calculated as follows.
Charge inclusion rate [%] = (1−α / β) × 100
α is a 0.01% aqueous solution of a crosslinkable water-soluble polymer 0.01% aqueous solution adjusted to pH 4.0 with acetic acid by a PCD titration device (Mutek PCD-03, Mutek PCD-Two Titortor Version 2) manufactured by Mutech. 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 is 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 aqueous potassium polyvinyl sulfonate 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 copolymerization rate between a cationic monomer and an anionic monomer, the calculation is performed as follows.
Charge inclusion rate [%] = (1−α / β) × 100
α is a 0.01% aqueous solution of a cross-linkable water-soluble polymer adjusted to pH 10.0 with ammonia by using 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 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 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.

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 molecular weight of the vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer obtained by polymerizing these monomers is in the range of 3 million to 30 million, preferably in the range of 3 million to 20 million.

In the present invention, the freeness improving formulation can be added in combination with other chemicals in addition to the vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer of the present invention. That is, an anionic or amphoteric polymer, bentonite or colloidal silica inorganic material can be appropriately added. As timing, it is added at the same time or after the addition of the vinyl polymerization crosslinkable water-soluble cationic or amphoteric polymer of the present invention. Moreover, chemicals other than the freeness improving formulation, for example, filler, paper strength agent, sizing agent, coagulant, and sulfuric acid band can be added simultaneously.

  There are no particular restrictions on the location of the vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer of the present invention, but it is preferably before or after a fan pump or screen close to the wire part of the paper machine.

The vinyl polymerized cross-linkable water-soluble cationic or amphoteric polymer having a charge encapsulation rate of 15% or more and 90% or less used in the present invention is a so-called cross-linking as compared with a water-soluble polymer having a charge encapsulation rate of less than 15%. The cross-linked structure increases the number of sites that bind to the surface of the pulp fibers and fillers contained in the papermaking raw material, particularly the fine fibers, and promotes adsorption. Since it is in a clogged state, the water in the formed flock is likely to be liberated, and it is considered that a high drainage effect and a squeezing effect can be obtained. When the charge inclusion rate is higher than 90%, the crosslinking proceeds too much, which is disadvantageous because the addition amount increases, the yield effect, the drainage and the water squeezability decrease.

The effect of the present invention is exhibited when the charge inclusion rate is 15% or more and 90% or less, but depending on the properties of the papermaking raw material such as papermaking raw material with a very high proportion of fine fibers, the charge inclusion rate is close to 15%. In some cases, the crosslinking ability of the polymerized crosslinkable water-soluble cationic or amphoteric polymer cannot cope with the floc-forming ability such as the flock forming ability and the water squeezing ability, and a high effect cannot be obtained. Therefore, a charge inclusion rate of 35% or more is preferable in order to cope with all papermaking raw materials.

Although it can be applied to any paper stock as the target paper stock, the effect is more exerted particularly on a paperboard that requires improved drainage, water squeezing and production efficiency with a minimum addition rate.

The present invention will be specifically described with reference to the following examples, but the present invention is not limited to the following 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, 17.4 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), 0.2% aqueous solution of methylenebisacrylamide 3 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 45 ± 2 ° C. and performing nitrogen substitution for 30 minutes, 0.1 g of dimethyl-2,2′-azobis (methyl 2-methylpropionate) 0.05 wt% of the body) was added to initiate the polymerization reaction. Polymerization was carried out at 45 ± 2 ° C. for 1.5 hours, and then the mixture was heated to 70 ° C. and kept for 1 hour to complete the reaction. 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 370 mPa · s. When the charge inclusion rate is determined by the colloid titration method and the above formula, it is 36.5%, which is referred to as trial production-1. Further, by the same operation as in Synthesis Example 1, DMQ / AAM = 20/80 (mol%) charge inclusion rate 55.5% (prototype-2), DMQ / AAM = 40/60 (mol%) charge inclusion rate 46.5 % (Prototype-3), DMQ / AAM = 40/60 (mol%) charge inclusion rate 72.8% (prototype-4), DMQ / DMC / AAC / AAM = 20/10/5/65 (mol%) Crosslinkable water-soluble with charge inclusion rate of 54.6% (prototype-5), DMQ / DMC / AAC / AAM = 20/10/5/65 (mol%) charge inclusion rate of 80.6% (prototype-6) A polymer was synthesized. The results are shown in Table 1.

(Comparative 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, 80.1 g of deionized water, 88.6 g of 80% by weight acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 200.9 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) 07 g (0.035% 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, 5.0 g of polyoxyethylene polyoxypropylene alkyl ether (1% 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 450 mPa · s. When the charge inclusion rate is determined by the above calculation formula, it is 12.9%, which is set to trial production-7.
The results are shown in Table 1. Further, a crosslinkable water-soluble polymer having DMQ / AAM = 40/60 (mol%) and a charge inclusion ratio of 93.6% was synthesized by the same operation as in Comparative Synthesis Example 1 (prototype-8).

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

Yield rate measurement test was performed with a Brit dynamic jar tester. Use 200 mesh wire. The raw material used was a paperboard liner raw material having a solid content concentration of 0.52% by mass and a 23.9% solid content concentration as Ash for bringing in used paper. The physical properties of the papermaking raw materials are pH 7.2, Whatman No. The amount of cation required using PCD-03 model of 41 filter paper filtrate manufactured by Mutex is 0.003 meq / L, the fine fiber fraction that passed through a 125P screen (equivalent to 200 mesh) is 43.9% vs. solids concentration. is there. Synthetic example prototypes 1 to 6 were added at 200 ppm with respect to the solid content of the paper, and stirred for 30 seconds at 1000 rpm, and the filtrate was collected for 30 seconds. After filtration with two filter papers, SS was measured, and the total yield was measured. Then, the filter paper was ashed at 525 ° C. for 2 hours, and the ash yield was measured. The results are shown in Table 2.

(Comparative Example 1) Using the same papermaking raw materials as in Example 1, 200 ppm of Synthetic Example Trial-7, Trial-8, and Polyethyleneimine (BASF, Polymin SK) were added to the solid content of the paper. After stirring at a stirring speed of 1000 rpm for 30 seconds, the filtrate was collected for 30 seconds, and ADVANTEC, no. After filtration with two filter papers, SS was measured, and the total yield was measured. Then, the filter paper was ashed at 525 ° C. for 2 hours, and the ash yield was measured. The results are shown in Table 2.

(Table 2)

When the prototypes 1 to 6 of Example 1 were added, a higher yield effect was exhibited than when the prototype 8 of Comparative Example 1 and polyethyleneimine were added. Since the charge inclusion rate of Prototype-8 is outside the range of the present invention, it is surmised that the adsorption to the papermaking raw material is poor and the yield effect is lowered. Prototype-7 shows a yield effect similar to that of the example, but has a low charge inclusion rate, so-called strong linearity, and forms a coarse floc by cross-linking adsorption action with a long molecular chain, resulting in excessive moisture. It is thought that has been incorporated. Polyethyleneimine had a low molecular weight, and the yield effect was markedly reduced at the same addition rate as in the examples.

Using the same paper material as in Example 1, a measurement test of drainage and sheet moisture content was performed using a dynamic drainage tester DDA (Dynamic Drainage Analyzer, manufactured by Matsubo). The papermaking material is put into a DDA stirring tank with a 315 mesh wire at the bottom. Trial samples 1 to 6 were added at 200 ppm with respect to the solid content of the paper, stirred for 30 seconds at 500 rpm, and then the paper was sucked under a reduced pressure of 300 mBar to form a sheet on the wire. The moisture content of the formed sheet was measured over time. The drainage time was used as an index of drainage on the wire, and the shorter the drainage time, the better. On the other hand, the moisture content of the sheet is an index of water squeezing. The results are shown in Table 3.

(Comparative Example 2) Using the same paper material as in Example 1, a test for measuring the freeness of water and the water content of the formed sheet was conducted using the dynamic freeness tester DDA under the same test conditions. Trial-7, Trial-8, and polyethyleneimine (BASF, polymin SK) were measured for the drainage time when 200 ppm was added to the solid content of the paper and the moisture content of the formed sheet. The results are shown in Table 3.

(Table 3)

In Example 2 using the prototypes 1 to 6 of the present invention, compared to Comparative Examples 2-2 and 2-3, the drainage time is shortened, and it can be confirmed that the drainage is good. Further, the sheet moisture content is low and the water squeezing is improved. In Comparative Example 2-1, the drainage time is about the same as that in Example 2, but the water content of the sheet is higher than that in Example because excessive moisture was taken in, resulting in a decrease in water squeezing and a decrease in drying efficiency. became.

  As described above, according to the present invention, a high yield effect was exhibited, and it was confirmed that drainage and squeezability were good. This maintains the high yield of the papermaking raw material on the wire in the paper making process, and also improves the paper making speed in the wire part by improving the drainage and water squeezing, improving the water squeezing in the press part, and the dryer part. This contributes to the improvement of drying efficiency and solves the problem of improving productivity.

Claims (5)

A method for improving drainage, comprising adding a vinyl-polymerizable cross-linkable water-soluble cationic or amphoteric polymer having a charge inclusion rate of 15% or more and 90% or less to a papermaking raw material before papermaking. 10-100 mol% of a monomer represented by the following general formula (1) and / or (2) wherein the vinyl encapsulating water-soluble cationic or amphoteric polymer having a charge encapsulation rate of 15% or more and 90% or less , 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 method for improving drainage according to claim 1, wherein the method is polymerized.
General formula (1)
R1 is hydrogen or a methyl group, R2 and R3 are alkyl groups having 1 to 3 carbon atoms and alkoxy groups, and R4 is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and may be the same or different. A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X1 represents an anion.

General formula (2)
R5 represents hydrogen or a methyl group, R6 and R7 each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X2 represents an anion.

General formula (3)
R8 is hydrogen, methyl or carboxymethyl ^{group, Q} represents ^{SO3 -, C6H4SO3 -, CONHC (} CH3) 2CH2SO3 -, C6H4COO - or ^COO -, R9 is hydrogen or ^COO - ^Y2 +, Y1 or Y2 is hydrogen or a cation Represent each. 3. The method for improving drainage according to claim 1, wherein the vinyl polymer-based cross-linkable water-soluble cationic or amphoteric polymer has a charge inclusion rate in the range of 35 to 90%. 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 4. The method for improving drainage according to any one of Items 1 to 3.   The method for improving drainage according to claim 1, wherein the papermaking raw material is a papermaking raw material for paperboard mainly composed of waste paper.