WO2017110868A1

WO2017110868A1 - Polyacrylamide-based papermaking additive, method for producing same, and method for producing paper

Info

Publication number: WO2017110868A1
Application number: PCT/JP2016/088084
Authority: WO
Inventors: 雄貴蝦名; 孝治吉谷; 英夫茨木
Original assignee: 星光Pmc株式会社
Priority date: 2015-12-25
Filing date: 2016-12-21
Publication date: 2017-06-29
Also published as: CN108026699B; KR102063409B1; KR20180072706A; JP6593455B2; CN108026699A; JPWO2017110868A1

Abstract

The present invention pertains to: a polyacrylamide-based papermaking additive including an aldehyde-functionalized polyacrylamide which has excellent paper-strengthening effects and provides satisfactory water-filterability; and a method for producing paper by using the polyacrylamide-based papermaking additive. The polyacrylamide-based papermaking additive includes an aldehyde-functionalized polyacrylamide (A) which is a dialdehyde compound adduct of an amphoteric polyacrylamide copolymer (a) including, as polymer structural units, (meth)acrylamide, a cationic vinyl monomer, an anionic vinyl monomer, and a (meth)allyl-group-including monomer, and which is characterized by satisfying various conditions.

Description

Polyacrylamide paper additive, method for producing the same, and method for producing paper

The present invention relates to a polyacrylamide-based paper additive containing aldehyde-functionalized polyacrylamide having an excellent paper strength enhancing effect and good drainage, and a method for producing the same. The present invention also relates to a paper production method using the polyacrylamide paper additive.

Various aldehyde-functionalized polyacrylamide-based papermaking additives are used in the papermaking process in order to improve the productivity of paper accompanying the speeding up of the paper machine or the quality of paper. Aldehyde functionalized polyacrylamide is generally produced by reacting glyoxal, a dialdehyde compound, with polyacrylamide. The aldehyde-functionalized polyacrylamide contains aldehyde groups having reactivity with cellulose in addition to containing amide groups having high hydrogen bonding ability in the polymer structure. For this reason, since a covalent bond can be formed with the hydroxyl group of cellulose, an excellent paper strength enhancing effect and drainage can be expected.

Aldehyde-functionalized polyacrylamide-based paper additive, for example, introduces 15 mol% or more of aldehyde functional groups with respect to amino groups or amide groups such as polyamines and (nonionic, cationic, anionic, or amphoteric) polyamides. A method for increasing the drainage of a paper machine by adding a polymer having a weight average molecular weight of 100,000 g / mol or more to a pulp slurry has been proposed (see Patent Document 1). In addition, a method for producing a cellulose-reactive functionalized polyvinylamide adduct by reacting a vinylamide polymer with a cellulose-reactive agent has been proposed (see Patent Document 2). Furthermore, dialdehyde-modified polyacrylamide excellent in paper strength enhancing effect obtained by reacting amphoteric or anionic polyacrylamide using a divinyl monomer with glyoxal has been proposed (see Patent Document 3).

However, these were not fully satisfactory in terms of paper strength enhancing effect and drainage.

Special table 2007-518896 Special table 2010-502800 WO2000 / 011046

The present invention provides a polyacrylamide-based papermaking additive containing an aldehyde-functionalized polyacrylamide having excellent paper strength enhancing effect and good drainage, a method for producing the same, and a method for producing paper using the papermaking additive. For the purpose.

The inventors of the present invention have studied earnestly, considering that improving the fixability of a polyacrylamide-based paper additive containing an aldehyde-functionalized polyacrylamide to a pulp leads to the solution of the above problems. Specifically, the ratio of (1) the aldehyde compound added to the aldehyde-functionalized polyacrylamide, (2) the number average molecular weight, and (3) the isoelectric point related to the ionic properties were examined. As a result, the aldehyde-functionalized polyacrylamide in which the above (1) to (3) are within a certain range is disadvantageous for the fixing efficiency to the pulp, even in the conditions where no sulfuric acid band is added and the electric conductivity is high. It was found that the paper strength enhancing effect was superior to that of aldehyde-functionalized polyacrylamide and the drainage was good, and the present invention was completed. It has also been found that by using the polyacrylamide papermaking additive containing the aldehyde-functionalized polyacrylamide of the present invention, the moisture content of the wet paper before drying the pulp sheet is lowered, and the water squeezing effect is improved.

That is, the present invention, which is a means for solving the above problems,
<1> A dialdehyde compound adduct of an amphoteric polyacrylamide copolymer (a) having, as a polymer constituent unit, a (meth) acrylamide, a cationic vinyl monomer, an anionic vinyl monomer, and a monomer having a (meth) allyl group A polyacrylamide-based papermaking additive comprising an aldehyde-functionalized polyacrylamide (A) characterized by satisfying all of the following (1) to (3):
(1) In the aldehyde-functionalized polyacrylamide (A), the amide reaction rate, which is the ratio of the amide group added with the dialdehyde compound to the amide group added with the amide group and the dialdehyde compound, is 3 ~ 20 mol%
(2) Aldehyde-functionalized polyacrylamide (A) has a number average molecular weight of 500,000 to 4,000,000 (3) Aldehyde-functionalized polyacrylamide (A) has a pH of 3.5 to 8.5 and an ionization degree of 0 meq / g <2> The addition for polyacrylamide papermaking as described in <1> above, wherein the molecular weight distribution of the aldehyde-functionalized polyacrylamide (A) having an isoelectric point is 2.0 to 8.0 Agent,
<3> The proportion of polymer structural units is (meth) acrylamide: 74.0 to 99.7 mol%, cationic vinyl monomer: 0.1 to 12.0 mol%, anionic vinyl monomer: 0.1 to 10.0 mol %, A monomer having a (meth) allyl group: 0.1 to 4.0 mol%, an additive for polyacrylamide papermaking according to the above <1> or <2>,
<4> The additive for polyacrylamide papermaking according to any one of <1> to <3>, wherein the cationic vinyl monomer of the polymer structural unit has a tertiary amino group,
<5> Amphoteric polyacrylamide copolymer (a) obtained by polymerizing (meth) acrylamide, a cationic vinyl monomer, an anionic vinyl monomer, and a monomer having a (meth) allyl group includes the following (1) to ( 5) a method for producing a polyacrylamide-based papermaking additive comprising aldehyde-functionalized polyacrylamide (A ′), wherein the dialdehyde compound (b) is reacted so as to satisfy the conditions of 5)
(1) The dialdehyde compound (b) has a molar ratio of 10 to 60% with respect to the amide group of the amphoteric polyacrylamide copolymer (a).
(2) the pH is 7.5 to 12.5,
(3) The temperature is 1 to 60 ° C.
(4) The concentration of the amphoteric polyacrylamide copolymer (a) before the reaction is 0.5 to 11.0% by mass,
(5) The time is 20 seconds to 4 hours. <6> The aldehyde-functionalized polyacrylamide (A ′) according to <5> is any one of the above <1> to <4>. A method for producing a polyacrylamide-based additive for papermaking, which is an aldehyde-functionalized polyacrylamide (A),
<7> The method for producing a polyacrylamide-based paper additive according to <5>, wherein the dialdehyde compound (b) is glyoxal,
<8> The polyacrylamide papermaking additive according to any one of <1> to <4> is added to the pulp slurry in an amount of 0.01 to 3% by mass based on the pulp solid content. , Paper manufacturing method.

According to the present invention, a polyacrylamide papermaking additive containing an aldehyde-functionalized polyacrylamide having an excellent paper strength enhancing effect and good drainage, a method for producing the same, and a method for producing paper using the papermaking additive Can be provided.

The polyacrylamide papermaking additive containing the aldehyde-functionalized polyacrylamide (A) of the present invention comprises (meth) acrylamide, a cationic vinyl monomer, an anionic vinyl monomer, and a monomer having a (meth) allyl group as a polymer constituent unit. Is a dialdehyde compound adduct of the amphoteric polyacrylamide copolymer (a).
The method for producing a polyacrylamide-based paper additive containing the aldehyde-functionalized polyacrylamide (A ′) of the present invention comprises (meth) acrylamide, a cationic vinyl monomer, an anionic vinyl monomer, and a monomer having a (meth) allyl group The amphoteric polyacrylamide copolymer (a) obtained by polymerizing is reacted with the dialdehyde compound (b) so as to satisfy the following conditions (1) to (5).
(1) The dialdehyde compound (b) has a molar ratio of 10 to 60% with respect to the amide group of the amphoteric polyacrylamide copolymer (a).
(2) the pH is 7.5 to 12.5,
(3) The temperature is 1 to 60 ° C.
(4) The concentration of the amphoteric polyacrylamide copolymer (a) before the reaction is 0.5 to 11.0% by mass,
(5) The time is 20 seconds to 4 hours

(Meth) acrylamide in the present invention is acrylamide or methacrylamide.

Examples of the cationic vinyl monomer in the present invention include a vinyl monomer having a primary amino group, a secondary amino group, a tertiary amino group, or a quaternary ammonium salt. These cationic vinyl monomers may be used individually by 1 type, and may use 2 or more types together. It is preferable to use a vinyl monomer having a tertiary amino group as the cationic vinyl monomer constituting the amphoteric polyacrylamide copolymer (a) because the effect of fixing to pulp is likely to increase when used as a papermaking additive.

Examples of vinyl monomers having a tertiary amino group include dialkylaminoalkyl (meth) such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and diethylaminopropyl (meth) acrylate. Acrylates; Dialkylaminoalkyl (meth) acrylamides such as dimethylaminopropyl (meth) acrylamide and diethylaminopropyl (meth) acrylamide; Hydrochloric acid salts of vinyl monomers having the tertiary amino group, and inorganic acid salts such as sulfates And organic acid salts such as formate and acetate of vinyl monomers having a tertiary amino group. Among these, dialkylaminoalkyl (meth) acrylates are preferable.

The vinyl monomer having a quaternary ammonium salt includes a vinyl monomer obtained by the reaction of the vinyl monomer having a tertiary amino group and a quaternizing agent, and a vinyl having a quaternary ammonium salt such as diallyldimethylammonium chloride. Monomer. Examples of the quaternizing agent include alkyl halides such as methyl chloride and methyl bromide; aralkyl halides such as benzyl chloride and benzyl bromide; dimethyl sulfate, diethyl sulfate, epichlorohydrin, 3-chloro-2-hydroxypropyltrimethylammonium chloride. And glycidyltrialkylammonium chloride. These tertiary amino groups or vinyl monomers having quaternary ammonium salts may be used alone or in combination of two or more.

Examples of the anionic vinyl monomer in the present invention include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, 2- (meth) acrylamide-N-glycolic acid and N-acryloylglycine; maleic acid, fumaric acid, itaconic acid, citracone Unsaturated dicarboxylic acids such as acids; unsaturated tricarboxylic acids such as aconitic acid and 3-butene-1,2,3-tricarboxylic acid; 1-pentene-1,1,4,4-tetracarboxylic acid and 4-pentene- Unsaturated tetracarboxylic acids such as 1,2,3,4-tetracarboxylic acid and 3-hexene-1,1,6,6-tetracarboxylic acid; vinyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2-methyl Unsaturated sulfonic acids such as propanesulfonic acid; unsaturated phosphonic acids such as vinylphosphonic acid and α-phenylvinylphosphonic acid; Sodium serial anionic vinyl monomers include alkali metal salts or ammonium salts or potassium salts. These anionic vinyl monomers may be used individually by 1 type, and may use 2 or more types together.

Among the above anionic vinyl monomers, unsaturated monocarboxylic acids and unsaturated dicarboxylic acids are suitable from the viewpoint of improving paper strength, and specifically include acrylic acid, 2-acrylamide-N-glycolic acid, itacone. Acids and their salts are particularly preferred.

The monomer having a (meth) allyl group in the present invention may be a monomer having a (meth) allyl group, and other functional groups such as an anionic group and a cationic group in addition to the (meth) allyl group. Even if it has, it is classified as a monomer having a (meth) allyl group. Specific examples include (meth) allylsulfonic acid or a salt thereof, (meth) allyl alcohol, (meth) allylamine, (meth) allyl ammonium salt, and the like. Of these, (meth) allylsulfonic acid or a salt thereof and dimethylhydroxyethyl methallyl ammonium chloride are preferable.

As the monomer in the amphoteric polyacrylamide copolymer (a) of the present invention, other monomers may be used as long as the effects of the present invention are not impaired. Here, the range that does not inhibit the effect of the present invention is a total of 100 mol% of (meth) acrylamide, cationic vinyl monomer, anionic vinyl monomer, and monomer having a (meth) allyl group in the amphoteric polyacrylamide copolymer (a). In contrast, 0 to 3.0 mol% of other monomers are more preferable.

Examples of other monomer components include nonionic vinyl monomers, crosslinking agents, and chain transfer agents. Examples of nonionic vinyl monomers include (meth) acrylic acid esters, (meth) acrylonitrile, styrene, styrene derivatives, vinyl acetate, vinyl propionate, and methyl vinyl ether. These may be used individually by 1 type and may use 2 or more types together.

Examples of the crosslinking agent include N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, and N-isopropyl (meth) acrylamide. N-substituted (meth) acrylamides such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and other di (meth) acrylates; Bis (meth) acrylamides such as N, N′-methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, hexamethylenebis (meth) acrylamide; triacryl formal, triallyl isocyanurate, N, N Diallyl acrylamide, N, N-diallyl methacrylamide, triallylamine, mention may be made of polyfunctional monomers such as 3-4 functional vinyl monomers such as tetramethylolmethane tetraacrylate. Moreover, a water-soluble aziridinyl compound, a water-soluble polyfunctional epoxy compound, a silicon compound, etc. can be mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, N-substituted (meth) acrylamide is preferable.

Examples of the chain transfer agent include known chain transfer agents such as alkyl mercaptans and 2,4-diphenyl-4-methyl-1-pentene. These may be used individually by 1 type and may use 2 or more types together.

The proportion of the monomer in the amphoteric polyacrylamide copolymer (a) is preferably 74.0 to 99.7 mol% of (meth) acrylamide, considering the ion balance and the reaction of the dialdehyde compound with respect to the amide group. The range is 0.1 to 12.0 mol% of vinyl monomer, 0.1 to 10.0 mol% of anionic vinyl monomer, and 0.1 to 4.0 mol% of monomer having (meth) allyl group, more preferably (meta ) 83.0 to 99.7 mol% of acrylamide, 0.1 to 8.0 mol% of cationic vinyl monomer having tertiary amino group, 0.1 to 7.0 mol% of anionic vinyl monomer, and (meth) allyl group The monomer is in the range of 0.1 to 2.0 mol%.

The amphoteric polyacrylamide copolymer (a) is not particularly limited with respect to its production method, and can be obtained by a known polymerization method. In order to improve the fixability to pulp as the papermaking additive of the present invention, it is preferable to polymerize the monomer component by dividing or dropping.

There are no particular restrictions on the number average molecular weight and molecular weight distribution of the amphoteric polyacrylamide copolymer (a), but the molecular weight increases upon reaction with the dialdehyde compound and exceeds the appropriate number average molecular weight and molecular weight distribution range. A number average molecular weight of 50,000 to 3,000,000 and a molecular weight distribution of 2.0 to 7.0 are preferred.

The aldehyde functionalized polyacrylamide (A) of the present invention is not limited with respect to its production method. For example, an aldehyde-functionalized polyacrylamide (A ′) obtained by reacting an amphoteric polyacrylamide copolymer (a) with a dialdehyde compound (b) so as to satisfy the following conditions (1) to (5): be able to.
(1) The dialdehyde compound (b) has a molar ratio of 10 to 60% with respect to the amide group of the amphoteric polyacrylamide copolymer (a).
(2) the pH is 7.5 to 12.5,
(3) The temperature is 1 to 60 ° C.
(4) The concentration of the amphoteric polyacrylamide copolymer (a) before the reaction is 0.5 to 11.0% by mass,
(5) The time is 20 seconds to 4 hours

The dialdehyde compound (b) to be reacted with the amphoteric polyacrylamide copolymer (a) is a group consisting of glyoxal, glutaraldehyde, 2,5-diformylfuran, 2-hydroxyadipaldehyde, succinaldehyde, and combinations thereof Selected from. Glyoxal is most preferable from the viewpoint of reactivity and drainage effect.

In the production method of the present invention, the amount of the dialdehyde compound (b) to be reacted with the amphoteric polyacrylamide copolymer (a) is the amide of the amphoteric polyacrylamide copolymer (a) from the viewpoint of reaction efficiency and effect. It is preferable to react by mixing 10 to 60% in molar ratio with respect to the group (production condition 1). By performing such a reaction, it is the ratio of the amide group added with the dialdehyde compound to the amide group added with the amide group and the aldehyde compound in the aldehyde-functionalized polyacrylamide (A). The amide reaction rate tends to be 3 to 20 mol%.

In the step of reacting the amphoteric polyacrylamide copolymer (a) and the dialdehyde compound (b), if the base is added as necessary to adjust the pH of the reaction solution to 7.5 to 12.5, the amphoteric polyacrylamide copolymer is reacted. This is preferable because the reaction between the polymer (a) and the dialdehyde compound (b) is promoted (production condition 2).

When the temperature at which the amphoteric polyacrylamide copolymer (a) and the dialdehyde compound (b) are reacted is in the range of 1 to 60 ° C., the amphoteric polyacrylamide copolymer (a) and the dialdehyde compound (b) This is preferable because the reaction of (Production conditions 3).

When the concentration of the amphoteric polyacrylamide copolymer (a) is within the range of 0.5 to 11.0% by mass, the predetermined molecular weight, intrinsic viscosity, aldehyde is suppressed while suppressing the thickening of the reaction solution. This is preferable because it is easy to adjust the amount of functionalized amide. (Production condition 4).

The reaction time of the amphoteric polyacrylamide copolymer (a) and the dialdehyde compound (b) is preferably in the range of 20 seconds to 4 hours, since the reaction between the polyacrylamide and the dialdehyde compound is promoted. (Production conditions 5).

The polyacrylamide papermaking additive containing the aldehyde-functionalized polyacrylamide (A) of the present invention satisfies all of the following (1) to (3).
(1) In the aldehyde functionalized polyacrylamide (A), the amide reaction rate, which is the ratio of the amide group added by the dialdehyde compound to the amide group of the (meth) acrylamide structural unit before the dialdehyde addition, 3 to 20 mol%
(2) There is an isoelectric point where the number average molecular weight of the aldehyde-functionalized polyacrylamide (A) is 500,000 to 4,000,000 (3) pH is 3.5 to 8.5 and the degree of ionization is 0 meq / g.

In the aldehyde-functionalized polyacrylamide (A), the amide reaction rate, which is the ratio of the amide group added with the dialdehyde compound to the amide group added with the amide group and the aldehyde compound, is 3 to 20 mol%. (Polyacrylamide (A) condition 1), more preferably 3 to 15 mol%. The amide reaction rate referred to in the present invention is calculated from an integration ratio of 179 to 181 ppm (aldehyde functionalized amide peak) and 182 ppm to 185 ppm (amide group peak) by ¹³ C-NMR measurement. When the amide reaction rate is less than 3%, the amount of aldehyde groups in the polymer is insufficient, and when it is higher than 20%, the polymers cause a cross-linking reaction with the dialdehyde compound due to excessive progress of the reaction. Insufficient amount of aldehyde groups. For this reason, the covalent bond between the cellulose by an aldehyde group cannot be formed, but it is disadvantageous for the paper strength improvement effect or drainage.

The number average molecular weight of the aldehyde-functionalized polyacrylamide (A) needs to be 500,000 to 4,000,000 (polyacrylamide (A) condition 2), more preferably 500,000 to 3,000,000. When the number average molecular weight is less than 500,000, the proportion of the low molecular weight polymer component that has a small contribution to fixing to the pulp is increased, resulting in poor fixing effect. On the other hand, if it exceeds 4 million, the pulp is agglomerated to cause deterioration of the paper texture, which is disadvantageous for the paper strength enhancing effect.
The number average molecular weight in the present invention refers to that obtained by GPC-MALS method in which a multi-angle light scattering detector is connected to GPC.

Aldehyde functionalized polyacrylamide (A) needs to exhibit an isoelectric point where the ionization degree is 0 meq / g between pH 3.5 and 8.5 (polyacrylamide (A) condition 3). When the isoelectric point is between pH 3.5 and 8.5, the polymer forms a complex by the ionic interaction of the cation and anion in the papermaking system, and the fixing effect to the pulp is enhanced. It is advantageous for drainage. The isoelectric point as used in the present invention is measured by a PCD electrometer, but is not limited to the above apparatus as long as the same principle can be measured.

The molecular weight distribution of the aldehyde-functionalized polyacrylamide (A) is preferably 2.0 to 8.0, more preferably 2.0 to 7.0. The molecular weight distribution is the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), and if it exceeds 8.0, it tends to cause excessive pulp aggregation. The aldehyde-functionalized polyacrylamide (A) having an appropriate molecular weight distribution is less likely to cause deterioration of the paper texture due to excessive pulp agglomeration, and is advantageous for the paper strength enhancing effect. The weight average molecular weight in the present invention required for obtaining the molecular weight distribution refers to that obtained by GPC-MALLS method in which a multi-angle light scattering detector is connected to GPC.

In the polyacrylamide papermaking additive of the present invention, the aldehyde-functionalized polyacrylamide (A) is a main component, and the proportion of the polyacrylamide based paper is preferably 60% by mass or more, more preferably 80% by mass based on the total solid content. It is preferable that
Further, the polyacrylamide papermaking additive of the present invention may contain an unreacted dialdehyde compound. In that case, it is preferable to add an acid to adjust the pH to 2.5 to 4.5 to stop the reaction with the dialdehyde compound to make an additive for papermaking. The reaction solution can be added to the pulp slurry as it is without lowering. Examples of the base used for pH adjustment include sodium hydroxide, potassium hydroxide, ammonia and the like, and examples of the acid include sulfuric acid, hydrochloric acid, acetic acid and the like. Moreover, antiseptic | preservative, an antifoamer, etc. may be contained.

Preferably, the polyacrylamide papermaking additive of the present invention is preferably added to the pulp slurry (hereinafter sometimes abbreviated as “internal addition”).

Pulp slurry is a slurry of pulp diluted with water. As pulp, bleached or unbleached chemical pulp such as kraft pulp and sulfite pulp; bleached or unbleached pulp such as groundwood pulp, mechanical pulp, thermomechanical pulp, etc .; waste newspaper, magazine waste paper, corrugated paper Examples include waste paper pulp such as deinked waste paper.

The polyacrylamide paper additive of the present invention is usually 0.01 to 3.0% by mass, preferably 0.05 to 2.5% by mass, more preferably 0.1 to 2.0% by mass per pulp solid content. % Is used. When an aluminum compound such as a sulfuric acid band or polyaninium chloride (PAC) is added, it is preferable to add 0.1 to 1.0% by mass per pulp solid content. Also, as a method of adding a polyacrylamide paper additive to a pulp slurry, a method of adding a polyacrylamide paper additive without using any aluminum compound, a polyacrylamide paper additive after adding an aluminum compound A method of adding an agent, a method of adding an aluminum compound after adding a polyacrylamide-based papermaking additive, a method of simultaneously adding an aluminum compound and a polyacrylamide-based papermaking additive, and the like. Also good.

In the production of the paper of the present invention, either an acidic system using aluminum sulfate or a neutral system using no or a small amount of aluminum sulfate may be used. Further, an acidic rosin sizing agent, a neutral rosin sizing agent, an alkyl ketene dimer sizing agent, an alkenyl or alkyl succinic anhydride sizing agent, and the like may be added to the pulp slurry. As a method for adding these sizing agents, after adding a sizing agent to a pulp slurry, a method of adding a polyacrylamide papermaking additive, a method of adding a sizing agent after adding a polyacrylamide papermaking additive, Examples include a method of adding a polyacrylamide paper additive to a sizing agent after diluting and premixing. Besides, fillers such as clay, kaolin, calcium carbonate, barium sulfate, titanium oxide, etc. in pulp slurry; sizing agents other than the above sizing agents, size fixing agents, internal paper strength agents other than the present invention (increasing dry paper strength) Agent, wet paper strength enhancer), antifoaming agent, pH adjusting agent, dye, fluorescent whitening agent, yield improving agent, and the like may be appropriately contained. The paper to be produced usually has a basis weight of about 10 to 400 g / m ² .

Furthermore, with a size press, gate roll coater, bill blade coater, calendar, etc., surface paper strength enhancer such as starch, polyvinyl alcohol, acrylamide polymer, surface sizing agent, dye, coating color, anti-slip agent, etc. as required It may be applied.

As described above, the papermaking pH of the pulp slurry obtained by adding the polyacrylamide papermaking additive of the present invention to the pulp slurry and adding other additives as necessary is 3.5 to 8.5. From the viewpoint of the paper strength enhancing effect, it is preferably 6.5 to 8.5. The papermaking pH in the present invention is the pH of the pulp slurry immediately before dewatering with the papermaking machine, and the pH of the pulp slurry immediately before dewatering with the papermaking machine generally corresponds to the pH at the inlet in the actual machine. .

The paper produced using the polyacrylamide papermaking additive of the present invention includes information paper such as PPC paper, photosensitive paper base paper, and thermal paper base paper, art base paper, cast coated paper, coated base paper such as high-quality coated paper, etc. Sanitary paper such as tissue paper, towel paper, napkin base paper, fruit bag base paper, cleaning tag base paper, decorative board base paper / wall paper base, photographic paper base, processed base paper such as base paper for food containers, heavy paper Examples include wrapping paper such as bifuran kraft paper and single gloss kraft paper, electrical insulation paper, liner, core, paper tube base paper, gypsum board base paper, newsprint paper, paperboard board, etc. Therefore, it is possible to give a useful paper strength enhancing effect to the paper made. Among these, it is particularly preferable to use paper that requires paper strength or paper that restricts the use of sulfuric acid bands (information paper, coated base paper, paperboard board). The paper referred to in the present invention includes paperboard.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. In each example, all parts and% are based on mass unless otherwise specified. The physical property value of each example is a value measured by the following method.

The number average molecular weight, weight average molecular weight, and molecular weight distribution were obtained by GPC-MALLS method in which a multi-angle light scattering detector was connected to GPC under the following measurement conditions.
HPLC: Agilent 1100 series column: SHODEX SB806MHQ manufactured by Showa Denko K.K.
Eluent: phosphate buffer containing sodium nitrate (pH 3)
Flow rate: 1.0 ml / min Detector 1: Multi-angle light scattering detector DAWN manufactured by Wyatt Technology
Detector 2: Suggested refractive index detector RI-101 manufactured by Showa Denko KK

(Production of amphoteric polyacrylamide copolymer (a))
Production Example 1
In a 1 liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction tube, 260.00 g of water and 126.81 g of 50% acrylamide aqueous solution as monomer (1) 10 g, 30% sulfuric acid aqueous solution 15.60 g, dimethylaminoethyl methacrylate 15.72 g, and sodium methallylsulfonate 1.27 g were charged. Next, the temperature was raised to 60 ° C. in a nitrogen gas atmosphere, 0.24 g of ammonium persulfate was added as a polymerization initiator, polymerization was started, and the reaction temperature was raised to 90 ° C. Thereafter, 180.00 g of water and 132.49 g of 50% acrylamide solution, 0.10 g of dimethylacrylamide, 5.40 g of acrylic acid, and 1.27 g of sodium methallyl sulfonate were added as monomers (2), and further, ammonium persulfate was added in an amount of 0.8. When 48 g was added and the estimated viscosity at 25 ° C. reached 3000 mPa · s, water 290.00 was added to obtain an amphoteric polyacrylamide copolymer (a-1) having a solid content of 15.0%. Table 1 shows the results of measuring the ratio (mol%) of the monomer units constituting the amphoteric polyacrylamide copolymer (a-1), the number average molecular weight, the weight average molecular weight, and the molecular weight distribution.

Production Examples 2-14, Comparative Production Examples 1-6
The amphoteric polyacrylamide copolymer (a-) having a solid content of 15.0% was prepared in the same manner as in Production Example 1 except that the compositions of the monomers (1) and monomers (2) were changed as shown in Table 1. 2) to (a-14) and (ra-1) to (ra-6) were obtained. The ratio (mol%) of the monomer units constituting the amphoteric polyacrylamide copolymers (a-2) to (a-14) and (ra-1) to (ra-6), the number average molecular weight, the weight average molecular weight, The results of measuring the molecular weight distribution are shown in Table 1.

Abbreviations in Table 1 are as follows.
AAm: Acrylamide DM: Dimethylaminoethyl methacrylate DMC: 2- (methacryloyloxy) -N, N, N-trimethylethaneammonium chloride DPA: N- (2-dimethylaminoethyl) acrylamide DADMAC: Diallyldimethylammonium chloride IA: Itacone Acid AGA: 2-acrylamide-N-glycolic acid AAc: acrylic acid SMAS: sodium methallylsulfonate HEMAC: dimethylhydroxyethylmethallyl ammonium chloride MET: mercaptoethanol MBAAm: methylenebisacrylamide DMAAm: dimethylacrylamide Mn: number average molecular weight Mw : Weight average molecular weight Mw / Mn: Molecular weight distribution

(Reaction of amphoteric polyacrylamide copolymer (a) with dialdehyde compound (b))
Example 1
In a 200 mL beaker, 12.69 g of 15% aqueous solution of amphoteric polyacrylamide copolymer (a-1) prepared in Production Example 1, 163.00 g of ion-exchanged water, and 40% aqueous solution of glyoxal as dialdehyde compound (b) 1 .16 g (35 mol% with respect to the amide group of copolymer (a)) was added, and the temperature was raised to 35 ° C. while stirring at 180 rpm. The pH at this time was 3.8. Subsequently, 2.66 g of 5.0% sodium hydroxide aqueous solution was added to adjust the pH to 10.0, thereby starting the reaction. After stirring for 30 minutes, 0.67 g of 30% aqueous sulfuric acid solution was added to adjust the pH to 3.0, and the reaction was stopped. Table 2 shows the reaction conditions between the amphoteric polyacrylamide copolymer (a) and the dialdehyde compound (b). Table 3 shows the results of measuring the number average molecular weight, the weight average molecular weight, the molecular weight distribution, and the amide reaction rate for the obtained polyacrylamide-based paper additive (A-1). The amide reaction rate was obtained by performing ¹³ C-NMR measurement with INOVA (400 MHz) manufactured by VARIAN.

The degree of ionization of the polyacrylamide paper additive (A-1) was adjusted by adjusting the polymer concentration to 0.1% by weight using a PCD electrometer PCD02 (manufactured by MUTEC) and adjusting the pH with an acid-base component. The aqueous solution was measured. As a result, the isoelectric point at which 0 meq / g was reached was pH 4.4, and it was confirmed that an isoelectric point was present in the pH range of 3.5 to 8.5. The results are shown in Table 3.

Examples 2 to 16 and Comparative Examples 1 to 10
Except that the amphoteric polyacrylamide copolymer (a) type, reaction temperature, pH, concentration, time, glyoxal amount (mol% vs. amide group of copolymer (a)) were changed as shown in Table 2. Was carried out in the same manner as in Example 1 to obtain polyacrylamide-based papermaking additives containing aldehyde-functionalized polyacrylamides (A-2) to (A-16) and (RA-1) to (RA-10) . Table 3 shows the results of measuring the number average molecular weight, molecular weight distribution, amide reaction rate, and isoelectric point of the obtained aldehyde-functionalized polyacrylamide in the same manner as in Example 1.

<Production and Evaluation of Paperboard Using Sulfuric Acid Band in Low Electrical Conductivity Waste Paper Pulp Slurry>
Application Example 1
0.5% by mass of a sulfuric acid band was added to a pulp slurry of corrugated waste paper having a concentration of 2.4%, a beating degree (Canadian Standard Freeness) of 350, and an electric conductivity of 200 mS / m based on the pulp solid content. Next, 0.3% by mass of the polyacrylamide-based papermaking additive obtained in Example 1 was added to the pulp solid content in terms of solid content. After stirring this pulp slurry, the pulp concentration was diluted to 0.8% with water of pH 7.0, and then paper was made with a sheet machine made by The Noble & Wood, and after pressing, 100 ° C. with a drum dryer. For 120 seconds to obtain a paper having a basis weight of 80 g / m ² . The obtained paper was evaluated by the specific burst strength and internal bond described below. The results are shown in Table 4. Further, drainage was evaluated (DDT) after adjusting the pulp slurry in the same manner as described above until the pulp concentration was 0.8%. The results are shown in Table 4.

Specific burst strength: Performed according to JIS P8112.
Internal bond: Performed according to JAPAN TAPPI 18-2.

DDT: Tappi, Vol. 56, No. 10 (1973), page 46 of “Dynamic Drainage Jar”. 0.8%) Pour 500 mL into a 7.5 cm diameter jar, open the lower cock while stirring at 600 rpm, filter through a 100-mesh wire mesh, and measure the time to reach a certain filtrate volume. It can be used for evaluation of drainage. The time until the filtrate amount reached 100 g was measured. The smaller the value, the better the drainage.

Application Examples 2-32 and Application Comparison Examples 1-24
In Application Example 1, the same operation as in Application Example 1 was carried out except that the type of polyacrylamide paper additive and the mass% were changed as shown in Table 4, and a paper having a basis weight of 80 g / m ² was obtained. Obtained. The obtained paper was evaluated in the same manner as Application Example 1. The results are shown in Table 4. In addition, the drainage evaluation (DDT) was performed in the same manner as in Application Example 1. The results are shown in Table 4.

<Preparation and Evaluation of Paperboard with Low Electrical Conductivity Waste Paper Pulp Slurry and No Sulfuric Acid Band>
Application Example 33
Corrugated waste paper pulp slurry with a concentration of 2.4%, a beating degree (Canadian Standard Freeness) of 350, and an electrical conductivity of 200 mS / m is added with the polyacrylamide-based papermaking additive obtained in Example 1 as a solid in terms of solid content. 0.3% by mass was added to the minute. After stirring this pulp slurry, the pulp concentration was diluted to 0.8% with water of pH 7.0, and then papermaking was performed with a sheet machine made by The Noble & Wood. After pressing, 100 ° C with a drum dryer, The paper was dried for 120 seconds to obtain a paper having a basis weight of 80 g / m ² . The obtained paper was evaluated in the same manner as Application Example 1. The results are shown in Table 5. In addition, the drainage evaluation (DDT) was performed in the same manner as in Application Example 1. The results are shown in Table 5.

Application Examples 34 to 64, Application Comparison Examples 25 to 48
In Application Example 33, the same operation as in Application Example 33 was performed except that the type and mass% of the polyacrylamide papermaking additive were changed as shown in Table 5, and a paper having a basis weight of 80 g / m ² was obtained. Obtained. The obtained paper was evaluated in the same manner as Application Example 1. The results are shown in Table 5. In addition, the drainage evaluation (DDT) was performed in the same manner as in Application Example 1. The results are shown in Table 5.

<Preparation and Evaluation of Paperboard Using Sulfuric Acid Band in High Electrical Conductivity Waste Paper Pulp Slurry>
Application Example 65
A 0.5% by mass sulfuric acid band was added to a pulp slurry of corrugated used paper having a concentration of 2.4%, a beating degree (Canadian Standard Freeness) of 350, and an electric conductivity of 800 mS / m based on the solid content of the pulp. Subsequently, the polyacrylamide type papermaking additive obtained in Example 1 was added in an amount of 0.3% by mass with respect to the pulp solid content in terms of solid content. After stirring this pulp slurry, the pulp concentration was diluted to 0.8% with water of pH 7.0, and then papermaking was performed with a sheet machine made by The Noble & Wood. After pressing, 100 ° C with a drum dryer, The paper was dried for 120 seconds to obtain a paper having a basis weight of 80 g / m ² . The obtained paper was evaluated in the same manner as Application Example 1. The results are shown in Table 6. In addition, the drainage evaluation (DDT) was performed in the same manner as in Application Example 1. The results are shown in Table 6.

Application Examples 66 to 85, Application Comparative Examples 49 to 60
In application example 65, except having changed the kind of polyacrylamide type papermaking additive as shown in Table 6, operation similar to application example 65 was performed and the paper of basic weight 80g / m < ² > was obtained. The obtained paper was evaluated in the same manner as Application Example 1. The results are shown in Table 6. In addition, the drainage evaluation (DDT) was performed in the same manner as in Application Example 1. The results are shown in Table 6.

<Production and evaluation of paper using BKP>
Application Example 81
Concentrated 2.4% beating degree (Canadian Standard Freeness) 410, electric conductivity 100mS / m hardwood bleached kraft pulp (LBKP) / coat broke (CB) = 8/2 mixed pulp slurry, based on pulp solids Then, 0.1% by mass of a sulfuric acid band was added in terms of alumina, and then 0.3% by mass of the polyacrylamide internal paper strength agent obtained in Example 1 was added in terms of solid content. After stirring this pulp slurry, the pulp concentration is diluted to 0.8% with water at pH 7.5, and further 10% of calcium carbonate (Tama Pearl 121: manufactured by Okutama Kogyo Co., Ltd.) is added with stirring. Paper was made with a sheet machine made by Wood (TheNoble & Wood), and after pressing, dried with a drum dryer at 100 ° C. for 100 seconds to obtain paper with a basis weight of 60 g / m ² . The obtained paper was evaluated in the same manner as in Application Example 1. The results are shown in Table 7. In addition, the drainage evaluation (DDT) was performed in the same manner as in Application Example 1. The results are shown in Table 7.

Application Examples 82 to 112, Application Comparative Examples 61 to 84
In Application Example 81, except that the mass% of the sulfuric acid band and the type of polyacrylamide internal paper strength agent were changed as shown in Table 7, the same operation as in Application Example 81 was performed, and the basis weight was 60 g / m ^2. I got the paper. The obtained paper was evaluated in the same manner as in Application Example 81. The results are shown in Table 7. In addition, the drainage evaluation (DDT) was performed in the same manner as in Application Example 81. The results are shown in Table 7.

<Evaluation of water squeezing improvement in paperboard>
Application Example 113, Application Comparative Example 85
0.5% by mass of a sulfuric acid band was added to a pulp slurry of corrugated waste paper having a concentration of 2.4%, a beating degree (Canadian Standard Freeness) of 350, and an electric conductivity of 200 mS / m based on the pulp solid content. Subsequently, the polyacrylamide type papermaking additive obtained in Example 1 was added in an amount of 0.3% by mass with respect to the pulp solid content in terms of solid content. After stirring this pulp slurry, the pulp concentration was diluted to 0.8% with water at pH 7.0, and then vacuum dehydration was performed with a pulse sheet former (vacuum degree 30 kpa, 60 seconds) to produce a sheet having a basis weight of 400 g. did. Sponge and filter paper were placed on this sheet and pressed with a flat press at 4.2 kgf-1 for 1 second. The wet paper web moisture content after pressing was calculated from the weight of the sheet after pressing and the sheet dried at 110 ° C. for 2 hours. The results are shown in Table 8.

From Tables 4 to 7, the polyacrylamide papermaking additive of the present invention described in the examples is more pulpy than the polyacrylamide papermaking additive of the comparative example that does not satisfy even one of the configurations and conditions of the present invention. Regardless of the electrical conductivity and the presence or absence of a sulfuric acid band, it has excellent fixability to pulp, and is excellent at a level that satisfies paper strength and drainage.

From the results of application examples using the polyacrylamide type papermaking additive of Example 1, Example 6, and Example 7, the polyacrylamide type having a molecular weight distribution in the range of 2.0 to 8.0, which is more preferable. It can be seen that the papermaking additive is superior in the paper strength enhancing effect compared to the polyacrylamide type papermaking additive which is out of the range.

From the results of application examples using the polyacrylamide-based papermaking additive of Example 1, Example 9, Example 10, Example 11, and Example 12, the monomer units constituting the amphoteric acrylamide copolymer (a) It can be seen that when the ratio is within the more preferable range, the paper strength enhancing effect is more excellent.

From the results of the application examples using the polyacrylamide-based paper additive of Example 1, Example 8, Example 15, and Example 16, the cationic vinyl monomer unit constituting the amphoteric polyacrylamide copolymer is more preferable. It can be seen that the tertiary amine is more excellent in paper strength enhancing effect and drainage.

From Table 8, from the results of the application examples using the polyacrylamide papermaking additive of Example 1 and Comparative Example 1, the polyacrylamide papermaking additive of the present invention introduces an aldehyde group into the polymer structure. Thus, it can be seen that even when the monomer composition and the number average molecular weight are approximately the same, the moisture content of the wet paper is low, and in addition to the paper strength enhancing effect and drainage, the water squeezing improving effect is also excellent.

Claims

(Meth) acrylamide, a cationic vinyl monomer, an anionic vinyl monomer, and a dialdehyde compound adduct of an amphoteric polyacrylamide copolymer (a) having a monomer having a (meth) allyl group as a polymer constituent unit, 1)-(3) A polyacrylamide papermaking additive comprising an aldehyde-functionalized polyacrylamide (A) characterized in that all of the above are satisfied.
(1) In the aldehyde-functionalized polyacrylamide (A), the amide reaction rate, which is the ratio of the amide group added with the dialdehyde compound to the amide group added with the amide group and the dialdehyde compound, is 3 ~ 20 mol%
(2) Aldehyde-functionalized polyacrylamide (A) has a number average molecular weight of 500,000 to 4,000,000 (3) Aldehyde-functionalized polyacrylamide (A) has a pH of 3.5 to 8.5 and an ionization degree of 0 meq / g There is an isoelectric point
The additive for polyacrylamide papermaking according to claim 1, wherein the molecular weight distribution of the aldehyde-functionalized polyacrylamide (A) is 2.0 to 8.0.
The proportion of the polymer structural unit is (meth) acrylamide: 74.0 to 99.7 mol%, cationic vinyl monomer: 0.1 to 12.0 mol%, anionic vinyl monomer: 0.1 to 10.0 mol%, ( The additive for polyacrylamide papermaking according to claim 1 or 2, wherein the monomer has a (meth) allyl group: 0.1 to 4.0 mol%.
The polyacrylamide papermaking additive according to any one of claims 1 to 3, wherein the cationic vinyl monomer of the polymer constituent unit has a tertiary amino group.
The amphoteric polyacrylamide copolymer (a) obtained by polymerizing (meth) acrylamide, a cationic vinyl monomer, an anionic vinyl monomer, and a monomer having a (meth) allyl group has the following (1) to (5): The manufacturing method of the additive for polyacrylamide type paper manufacture containing the aldehyde functionalized polyacrylamide (A ') characterized by making a dialdehyde compound (b) react so that it may become conditions.
(1) The dialdehyde compound (b) has a molar ratio of 10 to 60% with respect to the amide group of the amphoteric polyacrylamide copolymer (a).
(2) the pH is 7.5 to 12.5,
(3) The temperature is 1 to 60 ° C.
(4) The concentration of the amphoteric polyacrylamide copolymer (a) before the reaction is 0.5 to 11.0% by mass,
(5) The time is 20 seconds to 4 hours
A polyacrylamide characterized in that the aldehyde-functionalized polyacrylamide (A ') according to claim 5 is the aldehyde-functionalized polyacrylamide (A) according to any one of claims 1 to 4. Of manufacturing additive for papermaking.
The method for producing an additive for polyacrylamide papermaking according to claim 5, wherein the dialdehyde compound (b) is glyoxal.
A method for producing paper, characterized in that 0.01 to 3% by mass of the polyacrylamide papermaking additive according to any one of claims 1 to 4 is added to the pulp slurry based on the pulp solid content.