JPH0718117B2 - Papermaking additives - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an additive for papermaking, which is particularly excellent in enhancing paper strength and improving water resistance. Furthermore, a filler and a sizing agent are used in combination. In the papermaking system, the retention of the filler and the retention of the sizing agent are increased.

[Technical background of the invention and its problems] Until recently, acidic papermaking using a sulfuric acid band was predominant in the papermaking process, but deterioration of paper obtained by acidic papermaking, corrosion of paper machines, etc. Due to serious problems such as difficulty in wastewater treatment due to the closed structure, papermaking in a neutral or alkaline pH range has been attracting attention instead.

With such a shift in papermaking pH, it has become possible to use inexpensive alkaline fillers such as calcium carbonate, which could not be used in acidic papermaking. Therefore, there is a demand for an excellent retention agent for paper strength agents, fillers and sizing agents that can be used for papermaking in the neutral to alkaline pH range.

Conventionally, acrylamide polymers have been known as those having excellent paper strength effect. Hoffman (Hofm
ann) rearrangement reaction, Mannich reaction, and copolymerization of a cation monomer and an anion monomer. Among them, the Hofmann rearrangement reaction product of polyacrylamide has been studied variously because of its excellent performance, but its stability has not been improved yet, and it is possible to avoid performance deterioration over time. I can't. See also Mannich
Under the neutral or alkaline papermaking conditions, the reaction product loses its cationic property and cannot exert a sufficient effect.

Further, although the copolymer has an excellent paper-strengthening effect, it has a poor aqueous and size retention effect. If the ionicity of the copolymer is increased in order to improve this drawback, there is a disadvantage that the cost becomes high.

The present inventors disclosed in JP-A-60-94697 that a water-soluble cationic monomer and / or salts thereof, α, β-unsaturated dicarboxylic acid and / or salts thereof, acrylamide and / or methacrylamide are essential constituent monomers. Disclosed is a paper strength agent comprising a water-soluble copolymer obtained as a component. Further, in JP-A-62-45798, dimethylaminopropyl (meth) acrylamide or its quaternary compound, itaconic acid or its salt and acrylamide are essential as paper-making additives useful for papermaking in the neutral to alkaline pH range. A water-soluble copolymer obtained as a constituent monomer component is disclosed.

However, it cannot be said in the above invention that all the drawbacks of the copolymer are solved.

Starch-based paper-strengthening agents are also widely used in comparison with these synthetic paper-strengthening agents. For example, they are used internally for the purpose of improving the surface strength of printing paper or used for coating with a size press. Is also used internally for the purpose of improving strength.

The characteristic of the starch-based paper strengthening agent is that it is cheaper than the synthetic type. Starch for internal addition, which is used for the purpose of strengthening paper strength, is generally chemically treated to have a cationic property, thereby increasing its own yield rate. However, the chemically treated cationized starch is not sufficient in its effect as compared with the polyacrylamide paper strengthening agent.

[Outline of Invention]

The present inventors have diligently studied papermaking additives that have excellent paper strength-enhancing effects, and particularly excellent retention effects of water, fillers and sizing agents. As a result, they are selected from starches, polyvinyl alcohols, celluloses and gums. At least one water-soluble polymeric substance (A), 0.1 to 20 mol% of a water-soluble cationic monomer and / or salts thereof, α, β-unsaturated dicarboxylic acid and / or salts thereof (C). ) A water-soluble polymer obtained by graft-copolymerizing a comonomer consisting of 0.1 to 15 mol% and acrylamide and / or methacrylamide (D) 99.8 to 65 mol% has particularly excellent performance, and is a broke paper for papermaking. It has been found that when an inexpensive water-soluble polymer substance is used, the cost is lower than that of the copolymer and the industrial usefulness is significantly improved. Led was.

The starches are not particularly limited, and examples thereof include raw starch such as potato starch and corn starch, and dextrin, oxidized starch, dialdehyde starch, alkyl etherified starch, cationized starch, phosphate starch, urea phosphate starch and the like.

Any PVA can be used as long as it is water-soluble, and its ionic type does not matter.

Representative examples of celluloses include carboxymethyl cellulose, hydroxyethyl cellulose, cationized cellulose and the like.

As gums, guar gum, locust bean gum and their derivatives (phosphorylated, hydroxyethylated,
Those subjected to modification treatment such as carboxymethylation).

Representative examples of the water-soluble cationic monomer as the component (B) include dimethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide and diethylaminopropyl (meth) acrylamide. A vinyl monomer having a tertiary amino group and a salt of an inorganic or organic acid such as sulfuric acid or acetic acid, or a quaternization of the tertiary amino group-containing vinyl monomer with methyl chloride, dimethylsulfate, epichlorohydrin, etc. A vinyl monomer containing a quaternary ammonium salt obtained by reaction with an agent, and a reaction of the vinyl monomer containing a tertiary amino group with a quaternizing agent such as 3-chloro-2-hydroxypropyltrimethylammonium chloride. 2-hydroxy-N, N, N, N ', which is a reaction product of bis-quaternary ammonium (meth) acrylamide and the like, such as dimethylaminopropyl (meth) acrylimide and 3-chloro-2-hydroxypropyltrimethylammonium chloride. N'-pentamethyl-
N '[3-[(1-oxo-2-propenyl) amino]
Propyl] -1,3-propanediaminium dichloride. Among these monomers, the amide-type cation monomer is superior to the ester-type cation monomer, but this is because the amide-type cation monomer is less susceptible to hydrolysis and retains its cationicity even in the neutral to alkaline pH range. It is thought to be because.

Representative examples of the component (C) α, β-unsaturated dicarboxylic acid and salts thereof include maleic acid, fumaric acid, itaconic acid, citraconic acid and their sodium, potassium and ammonium salts. To be Above all, itaconic acid and its salts have the best effect.

Examples of the monomer of the component (D) include acrylamide and methacrylamide. From the economical viewpoint, acrylamide is preferable, but both may be used in combination.

In the present invention, the amount of the water-soluble polymer substance (A) is 5 to 50% by weight,
The sum of the monomers of the components (B), (C) and (D) is
It is carried out in the range of 50 to 95% by weight. When the amount of the water-soluble polymer substance (A) is less than 5% by weight, the yield effect of water and size is lowered. Further, when the water-soluble polymer (A) is 50% by weight or more, the paper-strengthening effect is reduced, and in the case of a polymer such as starch which is aged, the viscosity stability of the water-soluble polymer is reduced. .

The proportion of each monomer in the comonomer consisting of the monomers of the components (B), (C) and (D) is 0.1.
-20 mol%, 0.1-15 mol% and 99.8-65 mol%. Among these three components, the higher the ratio of the component (B) monomer, the higher the retention effect of the filler and the sizing agent tends to be, and conversely the paper strength increasing effect tends to be poor. This is because the higher the ratio of the component (B) monomer that becomes the cation site, the easier it is to adsorb and aggregate the filler and the sizing agent, and as a result, each has a high yield effect, but on the other hand, due to the hydrogen bond with the hydroxyl group of cellulose, It is considered that the paper strength decreases because the proportion of amide groups that are considered to exhibit the paper strength increasing effect decreases.

Additives for papermaking are required to have a paper strength-enhancing effect, an aqueous improving effect, and a retention effect for fillers and sizing agents, and it is important to balance these performances. The component (B) monomer has a composition in which each of these performances exhibits excellent effects.
0.1 to 20 mol%, component (C) monomer is 0.1 to 15 mol%,
The amount of the component (D) monomer is 99.8 to 65 mol%.
In addition to these three components, (i) α, β-unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid and salts thereof, (ii) styrene in an amount that does not impair the water solubility of the polymer,
Use of a hydrophobic monomer such as acrylonitrile, ethyl acrylate, or methyl methacrylate, (iii) a sulfonic acid group-containing monomer such as vinylsulfonic acid or styrenesulfonic acid, or a salt thereof, or the like prevents the present invention. is not.

The Brookfield viscosity (hereinafter abbreviated as viscosity) of the water-soluble polymer of the present invention is 300 to 10 when the concentration is 10% by weight.
0,000 cps (25 ° C., Brookfield type viscometer used ... abbreviated as B type viscometer hereinafter), particularly preferably 800 to 20,
It is 000 cps.

In the case of extremely low molecular weight (low viscosity), the yield effect is poor,
Further, in the case of extremely high molecular weight (high viscosity), the yield effect is excellent, but excessive aggregation causes adverse effects on paper strength.

Polymerization which essentially requires the water-soluble polymer substance (A), the components (B), (C) and (D) is carried out by a usual method.

That is, (i) a method using a cerium salt or hydrogen peroxide-based or ammonium persulfate-based redox-based initiator or a radical polymerization initiator such as benzoyl peroxide or ammonium persulfate as a polymerization initiator, (ii) radiation, electron Examples include a method of irradiating with rays and ultraviolet rays.

The polymers obtained by these polymerization methods are considered to be so-called graft polymers. That is, it is considered that the water-soluble polymer substance (A) is grafted with the polymer composed of the components (B), (C) and (D) monomers. The water-soluble polymer of the present invention comprises a water-soluble polymer substance (A) alone, a copolymer comprising components (B), (C) and (D) monomers alone, and further a water-soluble polymer substance (A) and a component (A). The reason why it is superior to the blend of the copolymers composed of B), (C) and (D) monomers in the paper-strengthening effect and the yield-improving effect of the filler and the sizing agent is not clear, but a water-soluble polymer substance It is considered that the synergistic effect of (A) and the copolymer was developed by grafting.

〔Example〕

Next, the present invention will be specifically described with reference to examples and application examples.
Unless otherwise specified, "%" means "% by weight". The chemical abbreviations are as follows.

AAm acrylamide DM dimethylaminoethyl methacrylate DPA dimethylaminopropyl acrylamide BQ 2-hydroxy-N, N, N, N ', N'-pentamethyl-N'-[3-[(1-oxo 2-Propenyl) amino] propyl] -1,3-propanediaminium dichloride MA …… maleic acid IA …… itaconic acid FA …… fumaric acid AA …… acrylic acid APS …… ammonium persulfate SH …… hypophosphorous acid Sodium Further, each measurement in the application examples was carried out according to the following methods.

Specific burst strength …… JIS P-8112 Specific compression strength …… JIS P-8126 DDT …… Tappi Journal Volume 56, No. 10 (1973) No. 46
Using a device similar to "Dynamic Drainage Jar" described on the page, pour 800 ml of pulp slurry into a container having a diameter of about 7.5 cm, open the lower cock while stirring at 800 rpm,
A 10-mesh wire gauze is passed through and the time until the liquid volume becomes constant is measured, and it can be used for evaluation of aqueous properties. Here, the time until the liquid volume reached 200 ml was measured.

Steckigt sizing degree ...... JIS P-8122 Filler content rate ...... JIS-8128 ash measurement value multiplied by 1.78, CaO
Amount converted to CaCO ₃ amount.

Dry pick: Printed with an RI printing tester (manufactured by Akira Seisakusho Co., Ltd.) and observed the paper peeling state with the naked eye to determine "dry pick resistance, excellent 5 to poor 1".

Wet pick: Using the RI printing tester, moisten the surface with a water supply roll, print, and observe the peeled state with the naked eye to determine "wet pick resistance excellent 5 to poor 1". I did.

Transmittance (TM) …… Paper makers conferance (1985,
Modified Hercules Dynamic described in p.171)
Pulp using a device similar to Drainage Tester (a structure in which pulp slurry is poured into a container of about 7.5 cm in diameter, air is sent from the bottom so as not to form a mat under stirring, and stirring and air supply are stopped at the same time) 300 ml of the slurry is poured into a container, 70 ml of the liquid is taken, and the transmittance (TM) of this liquid at 620 nm is measured. First Pass Ret
TM was used as a parameter of ention). That is, the higher the TM, the clearer the liquid, and the higher the yield.

Example 1 5.51% of cationized starch (corn starch was cationized with a tertiary cationizing agent, and a nitrogen content of 0.25% was added to a one-necked four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube. After cooking at 90 ° C for 20 minutes, cooling to 25 ° C and measuring with a B-type viscometer (60 rpm), the viscosity was 360 cps.) Gelatinization liquid 4
1.74 g was added. Furthermore, DM2.35g, IA0.78g, 50% AAm aqueous solution 39.66g, water 80.88g, 2% SH aqueous solution 2.24g were charged.
Then, the pH was adjusted to 4.1 with a 15% aqueous sulfuric acid solution. The proportions of constituent monomers are 5 mol% DM, 2 mol% IA, and 93 mol% AAm. The ratio of the total weight of DM, IA, AAm to the weight of cationized starch was 10: 1. The temperature was raised to 60 ° C. under the introduction of nitrogen gas, and 0.68 g of a 5% APS aqueous solution was added to disclose polymerization. afterwards
Keeping the temperature at 75 ℃, 1.5 hours after the start of polymerization 0.3% of 5% APS aqueous solution
When g was added and the temperature was kept at 75 ° C for 1.5 hours to complete the polymerization reaction, the nonvolatile content was 15.1% and the viscosity at 25 ° C was
An aqueous solution of 6800 cps was obtained. This is referred to as water-soluble polymer A-1.

Examples 2-4, except that the composition of the constituent monomer components as shown in Table 1 and the total monomer / cationized starch weight ratio were followed.
The same operation as in Example 1 was performed. However, SH and 15
The amount of the% sulfuric acid aqueous solution was changed so that the appropriate viscosity and pH were obtained. The property values of the water-soluble polymers obtained in each example are summarized in the same table.

Examples 5 to 16 and Comparative Example 1 The same operation as in Example 1 was carried out according to the blending of the constituent monomer components as shown in Table 2 and except that the total monomer / cationized starch weight ratio was 10: 3. It was However, APS,
The amount of SH and 15% sulfuric acid aqueous solution is appropriate viscosity and pH each time.
I changed it so that The property values of the water-soluble polymers obtained in each example are summarized in the same table.

Examples 17 to 19 The same operations as in Example 5 were carried out except that the water-soluble polymer substance and the constituent monomers shown in Table 3 were used. The property values of the water-soluble polymers obtained in each example are summarized in the same table.

The viscosity of the oxidized starch used was 90 ° C at a concentration of 20% by weight,
Cook for 20 minutes and then cool to 50 ° C. Type B viscometer (60
It was 310 cps as a result of measurement by rpm).

Urea phosphate starch is Nylgum A-160
(Matsutani Chemical Co., Ltd.) and carboxymethyl cellulose (CMC) used Serogen 7A (Daiichi Kogyo Seiyaku Co., Ltd.).

Example 20 The same four-necked flask as in Example 1 was charged with 7.0% polyvinyl alcohol (saponification degree 98.2%, weight average molecular weight 73900).
91.1 g was added. Raise the temperature to 60 ℃, 5% APS8 there.
2g was added. After holding at 60 ℃ for 5 minutes, DM2.83
g, IA1.56g, 81.05g of 50% AAm aqueous solution, then 15%
2.0 g of a sulfuric acid aqueous solution was added. The ratio of constituent monomers is DM2.5
Mol%, IA1.8 mol%, AAm95.7 mol%. Also, D
The ratio of total weight of M, IA, AAm to polyvinyl alcohol weight is 1
It is 0: 3. After adding sulfuric acid aqueous solution, the temperature was raised, and the reaction was carried out at 75 ° C for 2.5 hours. Nonvolatile content 19.7%, viscosity (25 ° C)
An aqueous solution of 00 cps was obtained. This is designated as water-soluble polymer D-4.

Examples 21 to 22 Urea phosphate starch (Nylgum A- was used as a water-soluble polymer substance using the constituent monomers shown in Table 4.
The same operation as in Examples 5 to 16 was performed except that 160) was used. The property values of the water-soluble polymer obtained in each example are shown in the same table.

Example 23 To a four-necked flask similar to that of Example 1 was added 138.8 g of a 5% Nylgum A-160 aqueous solution. Nitrogen gas 3
After blowing for 0 minutes, 39.46 g of 50% AAm aqueous solution, IA0.59 g, DPA
2.81 g and 92.7 g of water were added, and the pH was adjusted to 3.9 with 1N HNO ₃ . Cerium ammonium nitrate 0.24 g (1 NHNO ₃
(Dissolved in 10 g) was added, and the pH was adjusted to 1.1 with 1 NHNO ₃ . The temperature of this reaction solution was raised and kept at 40 ° C for 60 minutes.
The pH was adjusted to 4.1 with OH. The aqueous solution thus obtained had a nonvolatile content of 8.6% and a viscosity of 920 cps. This is a water-soluble polymer F
And

The ratio of the constituent monomers is DPA 6 mol%, IA 1.5 mol%, AAm 92.5 mol%, the total weight of DPA, IA, AAm and the weight ratio of Nylgum A-160 is 10: 3. .

Example 24 335.7 g of water was placed in the same four-necked flask as in Example 1 and nitrogen gas was blown for 10 minutes, 2.52 g of sodium hypochlorite having an effective content of 12.6% was added, and the mixture was stirred uniformly and then guar gum ( Product name: EMCOGU CSAA ... Sansho Co., Ltd. 4.67
g was added and the pH was adjusted to 10.3 with 5% NaOH. After stirring at room temperature for 10 minutes, the pH was adjusted to 3.1 with 7.5% H ₂ SO _4. Then 5
25.56g of 0% AAm aqueous solution, IA0.77g, DPA1.85g and water 10.0g
A mixed solution containing nitrogen gas, which had been previously blown with nitrogen gas, was added, and the mixture was stirred at room temperature for 40 minutes, heated to 55 ° C over 10 minutes, and reacted at 55 ° C for 1 hour. The thus obtained aqueous solution had a nonvolatile content of 5.2% and a viscosity of 2400 cps. This is designated as water-soluble polymer G.

The proportion of constituent monomers is DPA 6 mol%, IA 1 mol%, A
Am 93 mol%, and the weight ratio of the total weight of DPA, IA, AAm to guar gum is 10: 3.

Comparative Example 2 DM4.72g, IA1.56g, in the same four-necked flask as in Example 1.
A 50% AAm aqueous solution (79.36 g), water (214.0 g) and a 2% SH aqueous solution (4.48 g) were charged, and the pH was adjusted to 4.4 with a 15% sulfuric acid aqueous solution. The proportion of constituent monomers is 5 mol% DM, 2 mol% IA, AA
It is m93 mol%. The temperature was raised in the same manner as in Example 1 and APS was added. However, the first amount of 5% APS added was 1.37.
g, the second time was 0.68 g. The thus obtained aqueous solution had a nonvolatile content of 15.3% and a viscosity of 7400 cps. This is referred to as water-soluble polymer H.

Application Examples 1 to 15 and Comparative Application Examples 1 to 7 A 2.5% concentration slurry of beaten pulp having a Canadian Standard Freeness (hereinafter abbreviated as CSF) of 407 ml obtained from waste corrugated paper has 0.5% sulfuric acid band.
(Based on dry weight of pulp, the same applies hereinafter), and then the water-soluble polymers obtained in Examples 1 to 4 and Comparative Example 2 and cations used in the synthesis of A-1 to A-4. A mixture of modified starch, cationized starch and a water-soluble polymer in the same proportion as A-3 was added as a paper-strength agent in the amounts shown in Table 15.

After stirring for 2 minutes, the pulp slurry concentration is adjusted.
After diluting to 0.25% and stirring for another minute,
Papermaking with a hand-made machine made by Andwood (pH at the time of papermaking is
6.5) and then dried in a drum dryer at 110 ° C. for 90 seconds to obtain two types of handmade papers having a basis weight of 85 ± 2 g / m ² and 172 ± 3 g / m ² . In addition, DDT was measured using this 0.25% pulp slurry, and the water content was investigated.
The obtained handmade paper material is 24 ° C under the conditions of 20 ° C and 65% relative humidity.
After time humidity control, the specific burst strength was measured for the former basis weight stock and the specific compressive strength for the latter basis weight stock.
The results are shown in Table 5.

It has been found that the water-soluble polymers of the present invention are particularly superior in water to cationic starch alone, polyacrylamide copolymer alone, and blends of cationic starch and polyacrylamide copolymer. It was also found that the broke was easier to collect than the polyacrylamide copolymer alone, as indicated by the wet tear length value.

Application Examples 16 to 25 and Comparative Application Example 8 A 2.5% slurry of beaten pulp of 372 ml of CSF obtained from cardboard waste paper, to which 1.5% of a sulfuric acid band was added, was used as a sizing agent, "New For 100" (Dick Hercules 0.1% of rosin emulsion sizing agent manufactured by Co., Ltd., and then 0.4% of the water-soluble polymer obtained in each of Examples 8 to 16 and 22 was added as a paper strength agent. (As a comparative application example, 1.0% of the same cationized starch as in Example 1 was added.) Thereafter, in the same manner as in Application Examples 1 to 15 and Comparative Application Examples 1 to 7, the basis weight was 78 ± 3 g / m 2. ² and 160 ± 5 / m ² handmade papers were obtained. In addition, the water content was measured.

The pH during papermaking was 4.5. After that, 78 ± 3g / m ²
The specific burst strength and the Stoeckigt sizing degree were measured for a paper material having a basis weight of 1, and the specific compressive strength was measured for a paper material having a basis weight of 160 ± 5 g / m ² . The results are summarized in Table 6.

It was found that the water-soluble polymers of the present invention have superior aqueous and sizing retention effects than cationized starch. It was also found that the water-soluble polymer E-2 synthesized using the cationic monomer BQ was superior to the water-soluble polymer synthesized using the cationizing agent DM.

Application Examples 26 to 35 and Comparative Application Example 9 In Application Examples 16 to 25 and Comparative Application Example 8, the water-soluble polymers obtained in Examples 8 to 16 were used as paper strength agents to which 0.5% of the sulfuric acid band was added. 0.4% each was added (1.0% of the same cationized starch as in Example 1 was used as a comparative application).
Was added. ) Thereafter, in the same manner as in Application Examples 16 to 25 and Comparative Application Example 8, handmade papers having a basis weight of 85 ± 2 g / m ² and 173 ± 2 g / m ² were obtained. In addition, the water content was measured.

The pH during papermaking was 6.5.

The effects were measured in the same manner as in Application Examples 16 to 25 and Comparative Application Example 8. The results are shown in Table 7.

From Table 7, it was confirmed that the water-soluble polymer of the present invention has a superior aqueous effect and paper strength enhancing effect than the cationized starch. It was also found that the water-soluble polymer E-2 synthesized using the cation monomer BQ was superior to the water-soluble polymer synthesized using the cation monomer DM.

Application Examples 36 to 45 and Comparative Application Examples 10 to 12 20% calcium carbonate in 2.5% aqueous dispersion of pulp (LBKP / NBKP = 75/25, CSF371 ml), Example 5 of the present invention
7, 17-19, 21, 23-24 and 12 water-soluble polymer
%, And 0.4% of the water-soluble polymer obtained in Comparative Example 1.
%, As a comparative application, the cationized starch used in Example 1 was added as a paper-strengthening agent at 0.8 and 1.2%, respectively. Next, 0.1% of Harcon W (alkyl ketene dimer size agent manufactured by Dick Hercules Co., Ltd.) was added. This pulp slurry is diluted to 0.25% and noble and
Paper is made with a hand-made machine made of wood (pH 8.4 at the time of paper making), then dried with a drum dryer at 100 ° C for 90 seconds, and the basis weight is 65
A handmade paper of ± 2 g / m ² was obtained. The obtained paper material was conditioned under the conditions of 20 ° C. and a relative humidity of 65% for 24 hours and then subjected to each measurement. The measurement results are shown in Table 8.

From Table 8, it was confirmed that the water-soluble polymer of the present invention had an aqueous effect and a sizing agent retention effect which were superior to those of the cationized starch. Further, as the anion monomer,
From acrylic acid, which is an α, β-unsaturated monocarboxylic acid,
It was found that the α, β-unsaturated dicarboxylic acids maleic acid, fumaric acid and itaconic acid were superior. Above all, itaconic acid was excellent.

As the cation monomer, it was confirmed that DPA, which is an amide-type cation monomer, is superior to DM, which is an ester-type cation monomer.

Continuation of front page (56) Reference JP-A-60-94697 (JP, A) JP-A-58-132198 (JP, A) JP-A-58-115195 (JP, A) JP-A-58-186696 (JP , A) JP-B 50-12481 (JP, B1) JP-B 46-27249 (JP, B1) JP-B 45-6279 (JP, B1)

Claims (4)

[Claims] 1. At least one water-soluble polymer compound (A) selected from starches, polyvinyl alcohols, celluloses and gums, and a water-soluble cationic monomer and / or salts thereof (B) 0.1 to 20. Mol%, α, β
-Containing a water-soluble polymer obtained by graft copolymerizing a comonomer consisting of 0.1 to 15 mol% of an unsaturated dicarboxylic acid and / or salts thereof (C) and 99.8 to 65 mol% of acrylamide and / or methacrylamide (D) Papermaking additive. 2. The total amount of each of the monomers (B), (C) and (D) is 5 to 50% by weight of the water-soluble polymer compound (A).
The papermaking additive according to claim 1, which is 50 to 95% by weight. 3. The monomer (B) is dimethylamino (meth).
Acrylate, dimethylaminopropyl (meth) acrylamide and 2-hydroxy-N, N, N, N ', N'-pentamethyl-N'-[3-[(1-oxo-2-propenyl) amino] propyl] -1 The papermaking additive according to claim 1, which is at least one compound selected from 3,3-propanediaminium dichloride. 4. The papermaking additive according to claim 1, wherein the monomer (C) is itaconic acid or a salt thereof.